Gun Review: ATI Omni Gen2 Hybrid Polymer AR15 Lower

ATI has been competing with a number of other companies to create a true polymer lower for over a year now.  ATI had created the first OMNI polymer lower, which was reviewed here at TheFirearmBlog in February of 2013.  While the reviewer here had no problems with the lower, there are many cases described online of those lowers failing at the buffer tube collar and rear take down pin.  In response ATI created a second generation of the OMNI Lower, which has an aluminum block around the buffer tube collar and rear take down pin. While these changes appear to solve those earlier problems with polymer lowers, the new Gen2 Omni Hybrid rifles I received exhibited more serious problems.

My initial impression of the lower was that it is very light.  With a stock flat top upper the complete rifle weighed in right at 4.5lbs.  With a loaded steel 30rd magazine it weighs 6lbs.  That weight is pretty impressive for a complete rifle with a loaded magazine. That is where the impressive attributes for this rifle ended.  The first problem I had was the rear takedown pin.  In order to push the takedown pin through you either need a punch or a 5.56 cartridge.  This is not like a standard aluminum lower, where the take down pins protrude enough to push them out with your fingers, giving the shooter the ability to remove the upper in the field without any tools.  While you are more than likely going to have a 5.56 cartridge while out shooting, it is still an annoyance to me to have to strip a round in order to access the internal workings of the lower.

The second issue, and even more of an annoyance than the first, is that ATI built their own anti-walk system on this lower.  There is built up polymer above the trigger pins that are threaded and contains a

Right side of lower receiver, clearly shows the anti-walk system created by ATI.

Right side of lower receiver, clearly shows the anti-walk system created by ATI.

small slotted flush screw.  In the event of a fire control group (FCG) failure, you would need a small slotted screwdriver in order to remove the pins.  While generally removing the FCG is not a function of field stripping, the beauty of the AR design is that it can be done quickly with nothing more than a punch.  This lower requires the user to carry more tools into the field if they anticipate having to do FCG repairs.  Personally, I have never been an advocate for anti-walk devices on the AR platform in the first place.  Anti-walk system are available to those that choose to install them if there is a want or need to do so.  But there is a difference between installing your own, and being forced into an anti-walk system that is part of the lower.  Having fired my fair share of 5.56mm / .223 Rem. rounds from AR-15s and military M16s and M4s I have never once a problem with a FCG pin walking out and rendering the FCG inoperable.  While the inclusion of them might have to do with the polymer lower, they were not included on the first generation of ATI polymer lowers.

Shooting this rifle was a different feel from the standard AR15.  Something about the polymer, low weight and slow cycle speed combined to make the entire bolt carrier group (BCG) stroke very noticeable to the user.  During every shot down range, I was acutely aware of the BCG travelling rearward, then stripping a round and finally closing.  I was able to fire a total of three 30rd magazines of Federal XM193 55gr rounds before failures started.  After inserting a fresh Magpul Gen2 P-Mag and firing three round, the magazine spontaneously ejected from the rifle without the magazine release being pushed.  I collected the brass that had just come out of the rifle to inspect it for a pushed primer, pressure signs or an out of battery detonation.  I found the brass to be normal and uniform with all of the spent brass I had fired to this point.  I inspected the rifle for any signs of a problem or cracking in the lower and found none.  I then inserted the same magazine into the rifle, dropped the bolt which chambered a round and fired the round by pulling the trigger.  After firing the round, the next round in the magazine was a failure to feed (FTF), binding about halfway into the chamber.  I was able to clear the FTF, chamber a new round and then got a failure to eject (FTE) the spent casing.  I was able to manually cycle the action with the charging handle, chamber a new round and then fire the rifle again.  The rest of the magazine were all FTFs and FTEs.  I was able to look into the ejection port, and found that all of the FTF were

Out of tolerance magwell and magazine wobble caused the follower to miss the bolt catch on several occasions.

Out of tolerance magwell and magazine wobble caused the follower to miss the bolt catch on several occasions.

being caused by the round nosing down into the area below the feed ramps and binding the action of the rifle when the bolt was headed forward. I took the magazine out of the rifle, inserted an empty magazine and took notice of just how much that the magazine was able to move in the magwell.  At this time I also discovered that I was able to tweak the magazine, and remove it from the rifle without using the magazine release.  I did this several times, and even gave the rifle to a shooting partner who was also able to replicate the problem himself.  I was able to replicate this with a steel GI magazine, and also Gen1 and Gen2 P-Mags.  The last problem that the rifle was exhibiting was the bolt not locking back on the last fired round.  I was able to remove the upper, and see that the magwell was loose enough to cause the magazine follower to miss the bolt catch, and allow it to ride behind the follower, failing to lock the bolt back.  At this point I felt that the rifle no longer safe to continue shooting because of the problems I encountered, including magazine that fell out spontaneously, and the ability to remove the magazine without using the magazine release.

ATI was given the chance to send out another rifle for testing, in the event that the failures of the previous rifle were an isolated problem.  The serial number of the first rifle was AN000835, which would lead me to believe that this lower was #835 off the line.  The new rifle that was received was AN003357, which happens to be 2,522 down the line if the serial is an indication of the order of manufacture. The first impression of the new rifle was problematic, just out of the box at my local FFL was the charging handle bound inside the upper about halfway back.  This happened when picking up the rifle for the first time and checking to ensure the rifle was not loaded prior to handling it.  I was unable to get the charging handle to go either back into place or continue all the way to the rear.  My FFL, who also is a 07 manufacturer, had to get a hammer to get the charging handle free.  After replicating the problem, he made the remark “This rifle is probably unsafe, and if you were just a regular customer, I would not let it out of my shop. It would be going straight back to the manufacturer for a replacement or to be fixed.”

Knowing at that point I would not be shooting the new rifle.  Having a charging handle that binds in the upper could cause a catastrophic failure if it were to get free during shooting.  I took the complete rifle back to my bench and decided to try the charging handle in an upper I know is within spec, the handle did not move, or bind at all.  I took a Rainier Arms Raptor handle, which I know is a high quality handle, and within spec, and put it in the ATI upper on the new rifle, and got the same binding problem.  This led me to believe that the charging handle slot in the upper was not milled properly, and was unsafe to shoot.

Both rifles were taken to a highly regarded gunsmith in the local area for evaluation.  He took both rifles apart and found the measurements on both to be out of spec in several places, including the magwell and the magazine release.  We found that the magwell in both rifles was too large. Specifically it was

Out of spec magewell.  This magwell is .003" too wide and long, making the magazine unstable.

Out of spec magewell. This magwell is .003″ too wide and long, making the magazine unstable.

.003” too large both in length and width, leading to the magazine wobble that I experienced with both rifles.  The wobble, coupled with the flex in the polymer lower, caused the magazine to come free without using the magazine release on both rifles (#835 and #3357).  The charging handle slots in rifle #3357 are .002” too wide, and the rails that retain the charging handle in the slot were almost nonexistent.  This meant that the charging handle was able to bind inside the upper when the tabs bound on the out of spec retention rails.  He also found that the upper that was sent with rifle #3357 was fired, in his opinion, much more than the three factory rounds.  There was significant wear in the chamber and a large quantity of unburned powder in the chamber and bolt lugs.  Having not fired rifle #3357 myself, this was directly from the manufacturer in this condition.  The upper shows a build date of Nov 17th 2013, and shows 3 empty casings in the box with the rifle.  In his professional opinion both rifles were unsafe to shoot, and would not leave his shop if someone was to order them.  His final report to me was that both of these rifles were out of tolerance, and would eventually lead to someone getting hurt.


Circle shows incomplete polymer flow around the aluminum buffer collar. Click for larger image.

There were also several other small things that I noticed about the original rifle that was sent. The first was that the polymer flow at the buffer tube collar and aluminum block was incomplete.  This would lead me to believe that there was either a flaw in the mold used, or the polymer mixture itself.  Being that it is within the first 1000 produced, it is entirely possible that there were problems with the molding process, be it the heat used, polymer blend or the mold used.  While this particular issue does not look like it will be causing any structural issues, it is something to note that they were having what looks to be some flow issues.  In the new lower #3357, the flow issue looks to be resolved, and look to be within normal limits.  What stuck out in my mind was that if there were flow problems with lower #835, where else might there not be enough polymer material in a more critical place that is out of sight that might have caused a failure down the road.

One final note is that rifle #3357 came with was a safety certificate. The certificate also suggests that any regular maintenance, which would include cleaning, be done by a qualified gunsmith, or the safety of the rifle cannot be guaranteed.  While I will occasionally I will take a firearm to a gunsmith for a deep clean and inspection, I would never take a firearm in for routine cleaning.  This certificate would suggest that ATI is implying that if you cleaning the rifle, what can be considered as routine maintenance, and there was a failure or safety problem that it would be the fault of the owner and not ATI.  This appears to be a thinly veiled attempt to shift the blame for any problems with a poorly made, out of spec rifle onto the owner simply for doing what millions of gun owners do every day.



My conclusion of both of these ATI rifles is that they are unsafe.  I have shot a lot of AR-15s in my life, including military M16s and M4s during my time in the Coast Guard.  I have never felt unsafe shooting a semi-automatic rifle, no matter who the manufacturer was.  I own two rifles that some consider mid-grade in terms of quality, and have never felt that they are unsafe.   They might not be as tight tolerance wise or as accurate as a high end AR, but at the end of the day, they do not make me feel unsafe like these rifles did.  Personally, I would not buy an ATI OMNI Gen2 lower or complete rifle, I would not own one and I sure would not hand one of them to a loved one to shoot.  If one of these rifles was to have a out of battery detonation, or catastrophic failure the polymer would blow apart into small pieces, embedding itself into your arm, body, legs and face.  While aluminum can fail as well, it has been engineered to fail at certain places directing the blast and fragments away from the user.  This is why we have seen catastrophic failures, only to learn that the shooter walked away with nothing more than a small cut.

They have fixed the problem of the polymer failing around the rear take down pin and the buffer tube collar, but there are just too many other problems with them right now to be able to recommend that you run out and buy a polymer lower.  If you happen to want to build a nice, light rifle my suggestions would be to find a good aluminum lower, and build the rifle with light materials.  While some will call this a step in the right direction for polymer, it is still far from ready for the open market.  These rifles, as received from ATI are, in my opinion, coupled with the opinion of two gunsmiths, unsafe.  They are out of tolerance and can and will hurt someone that shoots them if ATI continue to sell them as built.  Save a few more dollars and get something better and more reliable made out of aluminum.  Remember, you are purposely setting off an explosion that is 3” from your face; safety is paramount and should never be compromised to save a few bucks.

In complete polymer flow around the aluminum collar block.

In complete polymer flow around the buffer collar aluminum block.

Out of spec magewell.  This magwell is .003" too wide and long, making the magazine unstable.

Out of spec magewell. This magwell is .003″ too wide and long, making the magazine unstable.
Left side of lower receiver, clearly shows the anti-walk system created by ATI.

Left side of lower receiver, clearly shows the anti-walk system created by ATI as well as the serial number plate and company name above the magwell..

Right side of lower receiver, clearly shows the anti-walk system created by ATI.

Right side of lower receiver shows the ATI Omni Hybrid logo and company name by rear take down pin.

Circle shows magazine release protruding beyond the magwell behind the magazine catch.

Circle shows magazine release protruding beyond the magwell behind the magazine catch, the left side of the magazine catch should be flush to the lower.

Out of tolerance magwell and magazine wobble caused the follower to miss the bolt catch on several occasions.

Out of tolerance magwell and magazine wobble caused the follower to miss the bolt catch on several occasions while shooting.

Out of tolerance magwell and magazine wobble caused the follower to miss the bolt catch on several occasions.

Out of tolerance magwell and magazine wobble caused the follower to miss the bolt catch on several occasions while shooting.

Steve (The Editor) writes: Two days ago, after I had edited the final copy of this review, I sent a copy to ATI and asked them if they would like to send us a response which I would post below. the article. As I always do, I made it clear that I would not alter the review in anyway. I did, however, agree with their comment (in the third paragraph below) that the two photos I had included of a cracked lower from another company (for comparison purposes) is confusing and I decided to removed them. Nothing else has been added or removed. Their response …

December 19, 2013

To the Firearm Blog, Thank you for offering us an opportunity to read and respond to this review prior to publication.

While we at American Tactical greatly appreciate the information presented in this review, we are unable to agree with or verify the issues stated by Mr. Cadle, as we have not received either of these firearms back for our own service department to review. The return process for the firearms sent to Mr. Cadle is now underway. Once received, our full‐time gunsmiths will check each gun against the information provided in this review, so that we may address any issues, should they be present.

We would also like to make it very clear that the images used in this review that depict a cracked buffer tube collar are NOT images of the Omni Hybrid lower receiver.

American Tactical also does not know the circumstances of the firearms in between the time they left our facility and were picked up by Mr. Cadle. We do not know if the firearms for this review were inappropriately handled prior to his arrival at his FFL to receive them. We only test fire three rounds through each final assembly for functionality prior to full cleaning and packaging of our products. For liability reasons these test firings are performed by teams of staff and recorded should we experience any issues. We are unable to explain the claim of more than three rounds fired and an unclean rifle prior to Mr. Cadle’s first inspection of the second rifle we sent him.

Polymer molded AR lowers are still a relatively new item in the Shooting Sports industry, and the American Tactical Omni Hybrid is the newest innovation in design for this developing market. We understand that new technologies, especially those that challenge conventional thoughts and perceptions can often be met with resistance. American Tactical has chosen to embrace this new technology and is fully confident in it; so much so, that all Omni Hybrid lower receivers come with our first ever offered Lifetime Warranty in addition to the standard 2 year warranty that accompanies our rifles.

Thank you,

American Tactical


  • nester7929

    No thanks. It may not be as light as polymer, but my metal lower functions perfectly. I’d buy a pencil barrel before getting a polymer upper/lower, if the weight was an important issue.

    • I agree, there are a lot of other things I would consider to build a light AR before I even considered a polymer lower.

      • Frank

        I think it all depends on the lower. I’ve never heard of complaints like this for the CAV arms lowers or whatever company makes them now. I never got why no ones done polymer lower with an integral collapsible stock. It seems like you could easily thicken up the stressed areas that way and still have an adjustable stock. Just make the rear end a non folding copy of the ACR and you’d be GTG.

    • Christiano

      Well said mate…nevertheless may I know the complete details from you?

      • nester7929

        Complete details regarding what?

    • Clint Notestine

      Ive had a polymer lower for 3 years and not a single issue and a lot of the problem but mine is a Plum Crazy.

  • Alex M

    I’d very much like a follow up to this regarding how ATI responds to & remedies the problems. I feel that not following up would be unfair to ATI. I understand the statistical improbability of getting 2 lemons in a row, but it is possible.

    • ATI had every opportunity to test the heck out of a rifle before sending the second one to ensure that the second one was not going to be problematic.. .The fact remains that these issues are being caused by rifles not milled/molded within spec. Yes it is possible to get two lemons… But when two rifles, 2500 apart in terms of build order come up with the same measurement problems that is not a lemon problem, that is a manufacturing problem. ATI made a bad product that is out of spec. Would they send another rifle to a consumer? Maybe, but how many would they send? How many rifles will it take to get one that is within spec, and not exhibiting the same flex problems. You can go on ad Infinitum…

      • Boss/EFR

        Sam ,my serial numbers are AN003291, AN003294 and AN003399 and there is no way I can build a functioning rifle out of these receivers period. My background with the Ar / M4 rifles is that I was a 2111 trained Marine Corps Armorer. I am very familiar with these rifles. Each year at my shop toward the end of the year we buy different brands of parts and build website examples and then camo or two tone or whatever in cerakote, then at the end of that business year we sell them off and build more. I could not sell rifles with these receivers -they won’t work period. Now like I said previously I have a Gen 1 rifle with the poly receiver and when you compare magwells there s a huge difference. My gen 1 rifle locks mags nicely a wide variety of mags. The gen 2 is an eye appealing design with a lot of improvements over the first gen poly lower. to remedy the cracking issue that occurred with the gen 1 poly lowers. My gen 1 has not cracked yet. When I got the gen 2 lowers in I was impressed with the overall look and design and I noted that the magwell was flared nicely to allow for easier mag insertion. Instead mag fit is so sloppy that it that mags don lock in place properly and the bolt catch slips off the back of the mag. Sams pictures show exactly what is happening. Now this is not the case with the first gen poly lowers their mag and my mags work and lock properly ,yes there is some play but that is no worse than any of the aluminum lowers that I have on hand. To make my second gen omni hybrid lowers work I would have to use some epoxy to fill in the bottom of the well and shape it til it would function by removing the excessive clearance. That’s not happening this is a brand new receiver and it should have the proper dimensions right out of the box, So I have three that are waiting to go back and be examined by ATI. I like the price and I like the overall look ,but the product has to work, I will hold back a final judgement on this product till I hear back from ATI. As its stand right now I have three useless lowers.

        • Interesting that the three you have are all right in the same time frame as the second one I received. 3357 was the second rifle I received.

          My findings are exactly what yours are here. The magwells are so sloppy that you cannot reliably use them, and to do so can/will end up in someone getting hurt.

          The gunsmith I used to check these out thinks the same thing you do, that the catch sticks so far into the magwell that the mag is able to partially activate it, while the slop and flex allow for extraction of the magazine. This would also explain the spontaneous ejection that I got while shooting.

          Sorry you have to put up with ATI. Having dealt with them in a limited capacity over this, I can definitely tell they also have some internal issues they need to work out. Seems that no two departments actually talk to each other, about anything….ever.

          Good luck to you. I really appreciate you telling your story. Just backs up, and reinforces that there are the same problems over all of these lowers, and we here at TFB are not the only one to notice the problems and bring them to the attention of ATI.

          • Boss/EFR

            just a quick update -ATI sent out RA tags and a shipping label so all three receivers are on the way back to ATI for their inspection.

          • Good to hear. They replacing them for you?

          • Boss/EFR

            They will be inspected by their gunsmiths and then I will be contacted. I will post back after talking with them. If they are not replacing them with receivers that will function then I will not have anything positive to say about this company going forward. I don’t expect to hear back from them until after the holidays.

          • Lance

            So, what’s the current word on ATI? I have, what I believe to be is the GEN 1 Omni, on hold for me right now pending my NICS. I saw it at the MPLS gun show today for $500! I him’d and haw’d for about 30 minutes and then finally told the dealer I would take it. For my 1st AR, is this going to be worth the $$$???

          • Boss/ EFR

            Hi Brian from EFR I received three replacements for the three receivers that I shipped back in Dec 2013 due to the magwell issue – built three ar 15’s last week and ran 100 rounds thru each rifle flawlessly in 20 degree weather last week using a variety of mags. ATI stood behind their product and I am happy with the end result. We will put a lot more rounds down range to insure no additional issues.and post back again in the future.

    • nester7929

      Business wise, it would be extremely dumb to send another bad product to
      a reviewer. Either ATI didn’t check the second one before sending it
      out, or the design itself is faulty. I don’t want to do business with
      them either way.

    • The response they gave is at the bottom of the article. We took every opportunity to be fair by testing a second rifle and offering ATI the choice of responding to this review.
      There is absolutely nothing remotely unfair. We’ve bent over backwards in every way to be fair. There is nothing to follow up on at this point. Any changes to the design or addressing QC issues is not a part of our responsibility.

  • My biggest concern was the safety of those potential customers/readers who might purchase these rifles.
    I certainly don’t take this lightly and I wish the test had been positive and we had been to present a good product to our readers.
    It rarely happens that we get something like this but it happened and it’s our duty to be honest and let you, the readers, decide based on what’s presented.

    • Christiano

      Absoloutely ….the customers is in terrific risk while using these products.

    • That was my first concern above everything else. The safety of the firearms community and the readers of this blog is priority number one, we are not talking about a faulty hammer that is out of spec, we are talking about a firearm that someone is going to hand to their spouse or child to shoot thinking that it was built right, inspected and is safe to shoot. I would feel pretty bad if I didn’t let people know what kind of product this was and heard of someone or their family member being injured.

  • Christiano

    @samcadletfb:disqus @disqus_80xQP3vezQ:disqus @disqus_rkNnpl8Zxi:disqus @Phil W “Senior Writer TFB”:disqus I very much agree with TFB in this regard. Also I have a personal opinion that I feel every prime manufacurer or brand should focus safety rather than only profit in business which unfortunately has become the prime motto nowadays. I think all of you should agree to me in this aspect. Also, righly as nester said, it is extremely foolish to send one after another a bad product for review to a reviewer.

  • Christiano

    Just heard about another widely known name, called AIRSOFTMEGASTORE. They are one of the biggest and trusted online Gun seller. Had received a few feedbacks from my close circles stating that they are user friendly, cheap and trustworthy. Just thinking of giving it a try. What say friends?

  • Nolan

    Man, it’s too bad this didn’t work out, I was kind of interested… Oh well, if I want a polymer lower I’ll just have to go with the new frontier armory one.

  • Found this this evening while looking at ATI’s FB…

  • Vhyrus

    I can’t comment on the rest of the issues, but a .003 difference in actual vs. specified dimension is generally well within standard dimension tolerances (usually ±.005). I have done work for gas turbines in which most of the tolerances are equal to or greater than .005 so I have a hard time believing a mag well on a rifle needs to be that tight.

    • I’d say the acceptable tolerances for a turbine would be different than for a rifle.
      Anytime a magazine wobbles and falls out without activating the mag release the dimensions are well off acceptable limits.

      • Vhyrus

        You’re right: a turbine needs considerably tighter tolerances in order to function properly. That’s entirely my point.

        .003 inches is roughly the average width of a human hair. A hair’s width is not going to be the difference between a working and non working rifle.

        • When you combine the .003 front and side does that not increase the overall dimension?

          • Vhyrus

            If it was .003 too wide from both the front and rear of the magazine then that is actually a .006 overall difference, which would usually be considered ‘out of tolerance’ for most applications. The article simply says .003 which usually means a total difference rather than a stacking tolerance.

            I certainly don’t mean to imply that you or the author is lying in any way about the gun or that the gun is better than you say it is. I am simply saying that the explanation for the failure doesn’t hold water from an engineering standpoint. Something else has to be going on to cause the mag to come loose like that.

          • The added room in the magazine well allowed for magazines to move more freely, and coupled with the flex in the polymer allowed for magazines to be removed from the rifle without the use of the release. When measured against a high end AR lower, the ATI magwell’s came in .003 larger in length and width. While not a huge number, it was enough to put a magazine in, wiggle it and say to yourself “that feel lose.” Was it within the set tolerance by the company, maybe. Some companies will scrap anything that is .001 out of spec.

            There may be something else going on, but I had a gunsmith, who is also an mechanical engineer look at the lowers and his determination was that the problem that we were having was caused by the magwell being overly large.

            Could we have done destructive testing and cut the thing apart to get to other areas to get calipers, mics, depth micrometers and the like in there, sure… but ATI wanted these back. And my boss, told me I can’t destroy the guns… So I am left with the expert opinion of a gunsmith/manufacturer to give me his best opinion on what he thinks is going on. Something was not right, and caused huge safety issues…

          • Matt

            A polymer lower receiver magwell can never be compared to an actual broached aluminum receiver magwell in terms of tolerances. The polymer receiver would need a slide that would have some sort of draft to it (1-3 degrees). You can sometimes tell the direction of pull based on the parting lines. Was the gunsmith measuring the magwell width at the top or bottom of the magwell? It makes a large difference.

            All in all, you are comparing a broach to an injection mold. They are two totally different processes so just take it with a grain of salt.

          • They are indeed different processes but the dimensions must be the same to function as designed.

          • This is incorrect. The measurement of the magwell is a spec that must be adhered to in order for the rifle to function. No matter if the lower was made of plastic, paper, metal or wood… The measurement should always be the same no matter what. I fail to see how the material that it is made of would change how the process to make something should make the measurements compared to a spec drawing different.

          • Jake

            And this is why you’re seeming to fail at the whole understanding engineering thing.
            The angle is crucial for injection molding a part, so that it will actually release from the mold. A *ton* of designs are done certain ways, to ensure they’re actually createable and at a competitive price.

            Happened to a friend doing an engineering project. The well known designer / architect came out with the most gorgeous plan and product design …. but it was simply impossible to build. Holes that couldn’t be reached, tiny long holes at crazy angles with bends, etc. Fun thing.

          • gunslinger

            so it’s .003 left/right out of spec and .003 front/back out of spec?

          • big daddy

            That’s the way I read it, that would be .006 too wide and .006 too long.

          • yes it is

          • J.T.

            That picture showing the mag catch was showing the magwell being off by a lot more than .003.

          • gunslinger

            i think the spec is the “bottom” of the mag well, not where the mag catch is.

          • Boss/EFR

            Sam is correct the magwell is way off , we picked up three of these to use for shop /website examples for our cerakote refinishing business and did not even get to the point where we had the lower attached to an upper – we knew we had a serious issue. You will have a mag catch issues, mag retention and possibly safety issues. I actually have one of their first gen rifles on hand to compare the the mag wells with as well as some standard aluminum lowers. The Omni hybrid will not solidly lock any of our mags including p-mags colt mags and metal mags including a first gen poly rifle and supplied company mag in place. To be fair I called ATI and they are sending out return tags and they will take a look at these lowers. Bottom line is that in their present state I good not sell a rifle to a customer knowing that it flat out won’t function or be totally safe at the range. In my opinion the bottom of the mag well needs a redesign. Overall I was impressed with the weight ,construction and appearance of this new lower,but none of that matters if it won’t function safe and properly. I will wait to get a response back from ATI and post that back. Till then our three projects will move forward with standard metal lowers or a different poly lower.

          • I’m glad you posted the experience you had with them. It certainly parallels our experience.
            I really would appreciate you letting us know how it turns out.

          • Really appreciate you sharing. Looks like you had exactly the same problem I had, which shows that this is not just a fluke. Do you happen to remember what the serial numbers were? I would be curious where the ones you hare were in line compared to the ones I had.

          • Measurements were taken from the top of the magwell where it is flat. Obviously measuring the magwell at the entrance would not work as it is on a slant, and they flared the magwell.

          • Nathan

            Ok, when I read this reply I knew I have to get it. I don’t know where comes the impression that 3 thou of tolerance is bad for the AR15/M16, I mean, have any of you guys have any facts to back up this statement? I will give you facts of the M16, please check the magwell part of the M16 blueprint (enclosed below, and I hope this doesn’t violate the ITAR in any way), read what’s on the red circles. What this means, that the design tolerance is 15 thou, unless otherwise specified. 15 THOU that’s really huge! and checking the mag well part on height and width the tolerance is not specified meaning that those 15 thou (HUGE) is considered to be between specification and is considered OK, So I don’t see any big problem here, but from those pics the problem appear to be of another kind, mainly that the magwell is in bad location (but not in size) or the mag release and bolt catch is in bad location, and I would bet that this is what’s really causing the problem.
            Please always check your facts before throwing in stuff, unless the 3 thou that was off is off at the maximum tolerance, hence 18 (15+3) thou off.

          • We did spend a good amount of time with the engineer who agreed with the findings.
            The other person who examined it independently of the other person is a well respected gunsmith and a class 7 manufacturer of AK’s.
            I know there are multiple problems but I honestlyy believe the magwell has a good deal to contribute to the problems.

          • Eric Zelna

            Wait, you were measuring them against a different AR lower? You weren’t comparing them to the actual design specs? That is probably the most unscientific method of evaluating the lower you could possibly use. What if the other AR lower was out of spec also? Why not just reference the published design blueprints?

            Depending on which dimension you’re referencing, 0.003 might be fine. But you’ll have to be more specific than “length and width”, there are a lot of different dimensions to the magwell to be concerned with.

            “That feel loose” as you put it, sounds like a much more accurate summary.

          • No I never got the impression you thought we were lying. In fact the measurements were taken by a gunsmith and another gunsmith who is also a 7 maker of AK’s. It was off .003 front to back and another .003 side to side.
            The mag latch in the photo shows it out of spec. It’s should be even with the magwell not however much inside the magwell.

  • DaveC79

    Disappointing.. I also find their response to the review just as disappointing..

    • big daddy

      They would have been better off saying nothing.

    • I tend to agree with you here. Their reply is disappointing for a company to go that direction on a product, instead of making a promise to fix the problem, and make it right for anyone who might have purchased one.

  • Dong Blak

    That droopy trigger guard.

    • gunslinger

      for gloves? MOE trigger guard?

      • Dong Blak

        It’s ugly.

  • JT

    so these are basically less safe than the Defense Dist. lower is purported to be? If it did last to 600rds as they claim?

    • That’s hard to say without impartial involvement.

    • Steve (TFB Editor)

      I would go with the ATI over what is really a tech demo any day. We wanted to review the Defense Dist. … they never got round to sending us one.

  • Rick Constant

    I was hoping these “new” lowers would be much better. Since it seems they are not quite ready for prime time yet has the author or anybody else had any experience with the lowers available from

  • JaredN

    It is refreshing to read a negative firearms review. Too many gunzines and gun blogs, like too many car magazines car blogs, like everything they test, even if it is a piece of junk.

    • We feel it’s our duty to present the facts as we see them. I would have a hard time living with myself if we gave it a pass and someone was injured. Ethics trumps most everything else.

    • That’s actually how I got into writing gun articles.

  • gunslinger

    ZOMG another glowing review…er i mean ad for a compa…

    oh wait.


    • Like I mentioned things like this don’t happen often but eventually we have one not up to par.

    • No problem. I just call them like I see them. If you make a good product, I will say so. If I have a problem, I will say that too… Personally I don’t give passes for problems. People are going to be spending their hard earned money on these products, and they should know what they are spending their money on.

  • gunslinger

    I’d be interested to see the comparison with the “broken buffer picture” if it was labeled “this was not ATI’s Lower” and “this IS ATI’s lower” i could figure that out.

    • I can assure you 100% the pic is of the ATI lower. We didn’t want to create any confusion so the other brand photo had to go.

      • gunslinger

        Phil, i don’t dubt the pictures shown are the ATI product. I was stating that i’d like to see the comparison picture, and that if properly labeled, how would anyone get confused.

        but then again…we have darwin awards and the myriad of web pages that are dedicated to showing how stupid people can be,

        • Ok I got ya now. We just talked it over and decided to go with it as is. Yes indeed Darwin is alive and well sometimes:-)

  • Greg Paulsen

    We have done a lot of design around the AR platform – we have to call out “shall be compatible with Magpul PMAG GEN_ magazines” as part of our specification so we don’t accidentally create an interference during CAD design. I’m interested to know if GI MAGS had the same issues. This may have been overlooked during their design.

    It is very difficult to retrofit an AR platform because the weapon is already very utilitarian and simple. The straight edges, buffer tube on lower, and 2-pin joining of the receivers was designed with metal in mind; even a reinforced mimic in plastic is still a mimic. If you look at polymer-based assault weapons like the Beretta ARX-160 or IWI Tavor you’ll see a very different approach to how parts join and are retained. Perhaps an improved polymer solution will need to think outside the box. I am a huge fan of polymer solutions – if their design makes sense for the application..

    • RickH

      I agree with this. I have no problems what so ever with plastics/polymers in firearms. Problems always seem to arise when trying to retrofit key components like receivers. Designing from the start with polymer materials is always the proper way to proceed.

      • It’s interesting you say that. That’s something I felt would be the best approach. I’d like to see an appropriate material added to the polymer to strengthen it and provide greater longevity.

    • Sam actually did write that in the review. He tried GI mags and about everything else. The results were the same.
      It’s still a young technology for gun applications. Eventually it will have it’s day.

    • Thomas Gomez

      I would love to see how a polymer lower holds up on an overgassed surpressed rifle or the constant impulse from a piston retrofitted system. I would be afraid to try a polymer lower in such configuration.

      Great write up Sam!

      • Thanks Thomas. I was planning on testing my piston upper on their lower. But then the failures began and I didn’t want to push my luck and blow something up.

  • Alex Nicolin

    That rifle is clearly a piece of junk, and the makers are downright dishonest. I hope they go out of business.

  • hami

    This is unfortunate because out of the 3 polymer lowers i have had the original ATI Omni had the best finish by far. Smooth sides, no rough edges, etc.

  • MZupcak

    I feel bad for the ATI guys. They used to be in my home town of Rochester, NY, but they had to move due to politics. Now they’ve got over three thousand (assuming their serializing is consecutive) worthless rifles!

    • Nobody feels good about it believe me. I strongly wish it had been otherwise.

    • Trust me, I don’t like having to write something like this. I can’t think of a gun writer that does. But the fact remains that I am here to review a product that they made, to sell to you the consumer. If I cannot objectively do that so you the consumer know how you are spending your money and making sure that what you are buying is safe then I have failed.

  • Clint Notestine

    Did anybody try and replace some of the parts…. perhaps they were crap

    • No we take them as is. It wouldn’t be right to modify them to function correctly. Besides that we aren’t allowed to do that.
      The dimensions were off so there’s nothing we could have done anyway. When the charging handle binds and the mag falls out there isn’t much you can do,

      • Tuulos

        First thing that comes to my mind is tightening the mag catch a couple of revolutions and see if it helps any. Most likely not but I had some trouble with it when building my first ar lower.

        • It didn’t help unfortunately. I understand the engineer that checked it over said it was a no-go.

        • The mag catch was tightened, and loosened and checked probably 20 times to see if there might be an optimal place for it… We found none.

  • Tuulos

    I’ll have to applaud ATI for sending out two rifles for a review without picking the best of the lot to send.

    At least I’m going to tell myself that because the thought that those two were their best rifles is too scary.

    • That is what I have been telling myself too… Kind of disappointing that they didn’t take the time on the second one to send what they considered their “best of the best.”

      Although from my experience with the rifles, there is no “best rifle.” They are all made from the same mold, and therefore are probably all out of spec.

      • Tuulos

        That is quite likely. Hopefully they can fix the mold and hire a better QC team because the current team certainly doesn’t seem to be up to the task.

  • IXLR8

    So the lower has a lifetime warranty as long as it is only cleaned by a gunsmith? I couldn’t even make this up. Unacceptable.

  • José Pulido

    This really stinks. The only real problem I ever saw with polymer lowers was possible failure at the buffer assembly, and I was hoping they’d solve it without creating new problems.

  • Mack

    so if i read correctly, you received two rifles to review and both had the same problems? i hope that was a bad batch and there not all like that!

    • Yes, two rifles…2500 apart in terms of manufacturing had exactly the same problems. Likely not a fluke, or two lemons.

      • Mack

        yes that seems way more then a fluke, i was hoping these would be a decent lower (college kid with not a lot of playing around money). but appreciate a nice honest review instead the norm in gun mags that everything is flawless!

  • CJS3

    In the picture of the polymer flow around the buffer collar, there looks to be a crack in the polymer on the right side (in the picture) of the lower. Right where the take down pin goes through.

    • You know, looking at that picture again, I think you are right. I have sever other shots, of the same area from different angles and I believe that is indeed a crack that formed in the lower… Here is the left side of the same lower which shows what appears to be a crack in the lower as well. Having inspected that area of the rifle very carefully for just such a failure, I am wondering just how it might have been missed. Although photos show things some times that you just cannot see with the naked eye.

      **Click picture for full size**

    • CJ I looked it also. I blew the image up, changed a few settings to try and bring it out and get a better idea. I’m just not sure if it’s a fairly deep scratch or a crack. To be fair I won’t guess either way.

  • DiverEngrSL17K

    While I am sure that advances in materials technology will provide strong, reliable and safe firearms products when properly engineered, I still prefer good old-fashioned, proven, solid high-quality gun steel in the primary components of my firearms — not aluminum, not polymers, not titanium, not “unobtanium”, or whatever. Keep it strong, and keep it simple. Just my personal preference based on hard experience, nothing more.

  • Cymond

    What a pity. I think it’s a nice looking lower, and I like some of the design features. Hopefully they’ll get these problems worked out in the future. Also, 4.5 pounds unloaded, really? You might want to check that because it’s hard to believe that’s possible. I’ve seen custom builds struggle to hit 5 pounds with a polymer lower, ultrathin barrel, skeletonized bolt carrier, lightened buffer, micro-dot sight, etc.

    “there are just too many other problems with them right now to be able to recommend that you run out and buy a polymer lower.”
    Now wait just a minute! The CAV-15 has an excellent reputation. Perhaps that big difference is that the CAV-15 has a fixed stock & pistol grip, and was reinforced in a lot of areas.

  • Chris

    I have an ATI lower and a Palmetto Armory upper. I can’t get the rear takedown pin thru for nothing. Is there a fix for this that I can do or is this a gun smithing job?

  • Mark N.

    GunsAmerica recently posted a glowing review of this lower. In commenting, I posted a link to this review and the issues about this lower Cadle described–which in fact were similar to the same defects they found but swept under the rug. This is the response the Administrator for GA posted in response to Cadle’s review:

    “You have to be careful with people who overstep their credentials. Reporting that the mag well is oversized is fine, but unless you are a structural engineer with experience in glass filled polymers,and you know the interworkings of the product, saying something is “unsafe” is really just labeling yourself as a self important fool. He assumes that the ring is only mounted in the ring, and that the other metal embeds are independent. It is all one triple serialized part, as we explained. He had mags fall out, fair enough. If you read between the lines of the response from American Tactical, they suspect that he took the gun apart before shooting it. That is one of the problems with internet reviewers. Unless the parent organization takes responsibility for the qualifications of their writers and actually edits the material, what you are reading and making your purchasing decisions against is just “content” for someone to sell ads against. That particular blog is owned and run by a guy who lives in New Zealand and doesn’t even use his real name. Because he has *your* eyeballs, the industry takes it seriously, to its detriment. The story of the Omni is very simple. They made the magwell a little too big because they were overcompensating for P-Mags. -ph”

  • andy

    I wish I would of read this article before I bought 2 of these one has had no problems the other is expericing all of these problems it has malfunctioned right out of the box

  • Joel Stancil

    I actually own a good one… still has a problem with the mag wobble and an occasional FTF…..but usually only when it needs cleaning…..and I always take it to a licensed gunsmith….mostly cause it is my first ar and I haven’t learned the takedown method yet

  • Shelby Jordan Taylor-Phillips

    Hey guys, I thought I would throw in my two cents just for grins. I picked up one of these rifles recently, and so far am relatively satisfied. Before anyone goes all arfcom, I have a DDM4v7, a RRA/Bushy 6.8 (my first AR from a nearly a decade ago), and a mega lower on DPMS MK12 upper, and a Ruger Sr556 6.8. I used colts in the AF security forces and this is not my first AR rodeo. Now as to the rifle, it doesn’t feel like my DD for certain, the gas block is blocky and can be unbolted with basic arm strength, no leverage needed(neg), the barrel nut is slightly misaligned(neg), the melonite looks good, the barrel is 1:7, the bcg is M-16 though no mpi hp marks(who cares, I’m not going to the Ghan with it), the mag catch works well with no possibility of removal under stress(I tried very hard to get it out) the mag does wobble though no feeding issues so far, the pins are easily removable with what most people carry in their pockets(not as important to me as the reviewer above) the fcg screws were a might buffered from the factory, but I am glad it has antiwalk pins because I have personally had even colt pins walk on me rendering the weapon useless until the pin is back in the hole, and install antiwalks on all my
    rifles. The bolt head sticks once the trigger is pulled. I isolated the issue by removing the gas tube and charging handle and dry firing, then opening the action and removing the bolt. It takes more force when the action has been fired. Might just need breaking in but I am gonna check headspace first. No issues at all with the lower. There is no polymer flow problem. They are designed with the metal insert exposed, as evidenced by webpage for this product showcasing one with the metal showing. Overall, the rifle has a lot of positives and a few lazy negatives that are reflected in the price. This is not a top tier uber delta rifle by any stretch, but only time and use will tell if its up to regular civilian use. I carry an AR everyday, everywhere(I live in the country) so we’ll see if its up to the task. Just pointing out my experience thus far, and hope that no one thinks I’m trying to refute the review.

    • Shelby Jordan Taylor-Phillips

      Update on my Omni Hybrid(full rifle). Magpul 20rounders(new curved ones not old straight ones) fit snug as can be in this rifle. I believe its because of both the curve and the little shelf magpul added to the back of this gen or magazines. 30rounders wobble but cannot come loose. Function is good. The rifle runs. No, I haven’t put 3000 rounds through it(for anyone who likes to say “put blah blah arbitrary round count through it then call me” and drops the mic),and don’t intend to because the zombie apocalypse isn’t coming, and I am not leaving Georgia for a third world country any time soon. ATIs QC is not up to snuff by any means,but their parts are pretty dang good. My guess is their rifle builders are pumping out guns in the typical mad corporate dash to sell as many as possible.But somebody over their reads the forums for buzzwords because the castle nut is staked, the gas key is staked better than any dpms or bushmaster, the feed ramps are huge, the commercial buffer tube(while slanted) is at least closer to spec than usual because my true CAR-15 colt stock fits like a glove whereas the stock that came on it wobbles like crazy. The upper lacks forge marks however so who knows where they come from and mine has a couple smalle dents under the finish meaning they could be blemished cheapos or just cheapos. So far the lower is the one thing I can find no issue with except the 30rd mag wobble. Overall, in today’s market its not bad for 500 bucks. Lot of potential here if the lower holds up. Just needs some polishing.

  • Turk

    I have to differ with the author of this article. I purchased an Omni lower in Nov. ’12 when the rush was on. It sat in the box and just recently did I decide to finish it. I purchased a blem PSA upper combo and LPK but during the assembly using a wrench to tighten the castle nut, I may have tweaked the polymer buffer tube threads a little (1st Gen Omni remember). The BCG would drag in the tube and I felt there was some misalignment. I contacted ATI and I was still within their two year warranty period. I boxed the lower up and returned it. I was sent a new Omni Hybrid in return and after assembling and shooting it I am quite pleased. The glass filled material is quite hard (I did have to sand a slight a few thousandths off the top strap for the charging handle to clear). I had no failures through P-Mags and GI aluminum mags and the bolt catch functioned as designed. The mags do fit a little more loosely in the well but I could not dislodge them by pulling or side-loading them. Customer service was excellent.

  • james

    Hey everyone. I recently won this rifle at a wounded war hero fishing rodeo and after reading this I have a question I would like to ask. The rifle is brand new and has not been fired yet. Should I sell the rifle and buy one with a aluminum lower?