.400AR – Another Wildcat Cartridge for the AR-15

So you want an AR-15 for hog hunting that can launch .40 cal (10mm) pills? This wildcat caliber might be what you are looking for. It is called .400AR and was developed for hog hunting. The designers had initial requirements to have the largest caliber that will allow having double stack loaded ammunition in magazines fitting into the AR-15 magazine well. They also wanted to have at least 2,000 ft-lbs (2,712 joules) of muzzle energy and be able to use one of common cartridge head sizes which would allow using an off-the-shelf AR-15 bolt.

The new cartridge also had to have a maximum pressure manageable by the AR-15 platform. The development of this cartridge started three years ago with the first chamber cut back in the summer of 2014. The designers came up with a .40 caliber cartridge which is based on 7.35x51mm Carcano case. Initially, they cut the Carcano case right below the shoulder which gave them a 1.6″ long case. However, later they changed the design and made the final case to be 1.7″ long. The Carcano case has head (.447″) dimensions identical to that of 7.62x39mm cartridge, which means that they could use 7.62x39mm or 6.5mm Grendel bolts.

1.6″ and 1.7″ cases

They started they tests with 200 gr .40 cal muzzle loader bullets and after a number of tests, they reached the set goals. The .400AR final load launches the 200 gr projectiles at a muzzle velocity of 2,312 fps with 2,374 ft-lbs of muzzle energy (at around 50K PSI of pressure). It also reaches pretty interesting numbers with .40 cal handgun bullets. Particularly, it pushes the 135 gr bullets at 3,042 fps.

I think the same results could be achieved if the cartridge was based on a .422 head size (.30 Remington, 6.8 SPC etc). But that would be a straight walled case whereas .400AR should have a slightly tapered one, which is good for feeding reliability. If the case taper is ignored, then they could use larger projectiles of .423 cal from .404 Jeffery cartridge with the .447″ case body diameter. But then again case taper is good and the .423 is a rather odd caliber compared to the 10mm/.40 cal.

There is a website dedicated to this cartridge, where you can read more about it by clicking here.

Hrachya H

Being a lifelong firearms enthusiast, Hrachya always enjoys studying design, technology and history of guns and ammunition. His knowledge of Russian allows him to translate and make Russian/Soviet/Combloc small arms related information available for the English speaking audience.
Should you need to contact him, feel free to shoot him a message at TFBHrachyaH@gmail.com


  • Haulin’ Oats

    Or I could just shoot 308 or 6.5 creedmoor. If eradication is your only concern, there’s nothing 50bmg cannot solve.

    • Veteran for Trump

      There would be no hog left.

      • Anonymoose
        • TheNotoriousIUD

          Im guessing not many people here have actually tasted wild boar meat. Its awful because they eat trash and dead animals. Youre basically eating natures garbage disposal.
          Ive had it mixed in sausage with fifty pounds of seasoning and it was almost palatable. I even had a wild boar pate’ at a restaurant in Houston.
          It was decent on toast but still nothing I would ever order again.
          Bottom line: They are pests that just need to be shot.

          • lucusloc

            I guess that depends on what they eat. Acorn fed wild bore is some of the best pork available. The foothills of California are overrun with them, and Cali is too stupid to start an effective eradication campaign, so if you are willing to pay the horrendous price for a few tags you can get a freezer full of some amazing meat.

          • TheNotoriousIUD

            I should have guessed that the hogs in Cali would only eat pure, organic health food.
            The ones in Texas eat crap.

          • lucusloc

            Doesn’t Texas also have issues with their hog management? I read somewhere that getting pig permits there was a pain. I live in Oregon, and all we need to hunt pig is a hunting license, and there is no bag limit because the state wants them gone. This policy actually works quite effectively because everyone wants one, so there are virtually none left. Maybe if Texas could think the heards a bit they would taste better.

          • TheNotoriousIUD

            There are no permits required and you can kill as many as you want. You can shoot them from helicopters, hot air balloons, zeppelins, u-boats, whatever with night vision, silencers and full auto.
            The herd should be thinner than a motherfu-ker but theyre still kickin’.

          • ostiariusalpha

            It should also be said that younger boars have less of the gamey flavor that older boars get from the nasty pig testosterone they produce. It’s not just what they eat.

          • lucusloc

            sound like I need to take a hunting trip to Texas. . .

          • TheNotoriousIUD

            There are several companies in South Texas that run helicopter hunting charters.

          • Anonymoose

            Does it come with a minigun?

          • TheNotoriousIUD

            Lol, no.

            1/4 megaton RPG.

          • noob
          • lucusloc

            I’d sign up for that. . .

          • noob

            While not impossible you’d probably need a forward observer to hit the hog with naval gunfire. Make for a good video tho.

          • lucusloc
          • oldman

            The reason is at three months old the sows can breed and have litters of 1 to 14. With gestation of between 114 to 120 days. They can breed almost faster then we can shoot them.

          • Marcus D.

            Wrong. Reports suggest that they ARE breeding faster than y’all are shooting them.

          • oldman

            True but we are trying.

          • Reef Blastbody

            Feral hogs in Texas are classified as a nuisance species, and you can shoot them pretty much year round.

            The real PITA is arranging hunts, and getting permission from land owners. Lot of farmers with huge acreage and hog problems want to charge hunters big $$$$ for the privilege of eradicating a nuisance that’s doing tens to hundreds of thousands of dollars damage to their soy crops or whatever. Not as many people taking them up on that as they’d hoped, as I recall.

          • lucusloc

            Maybe that is what I was thinking. I just remember reading that hog hunting in Texas was a PITA. I was not sure if I was remembering that correctly though.

            I do know that hunting hogs in Cali is annoying because tags are so expensive, especially for out of state hunters. Makes the whole thing basically not worth it, and the hogs proliferate because of it.

          • itsmefool

            Nope, just hunt on public land! While we don’t have nearly the size that other states out West do, we got plenty of hog. Just pick some WMAs in East Texas, get your APH and hunting license, them get after it!

          • Paul White

            250-300/day in the panhandle area :/ chaps my ass.

          • art frewin

            i would let them keep the pigs for that….

          • art frewin

            i can see them trying to make a little off the damage done. if they get greedy, money talks and no money talks loudest…

          • Paul White

            I’ve had some ribs off smaller ones that were pretty good.

          • TheNotoriousIUD

            Had it several ways and was tolerable at best. Not for me but I know a few people in south Texas who donate it to shelters.

          • art frewin

            i will not give 1 penny of my money to an anti gun state. money talks and no money talks loudest.

          • iksnilol

            Dangnab city slicker with your “palate”, you make me sicker than the pork.

          • Philthegardner

            I never eat boar. Piglets and sows. But any boar with teeth showing are NASTY.

          • art frewin

            dog meat???

          • Lloyd Esp

            Depends where you get them. I have had wild pig in Florida and it was damn good….not as good as the sugarcane pig or the mac nut pig in Hawaii! The sugarcane pig is soooo good! And the older ones all have terrible teeth! In the mac not forests you can hear them cracking the nuts at night….sounds like gun shots!

    • Kelly Jackson

      How are you going to shoot .308 out of standard AR like this cartridge can be fired?

      Hold this L please.

      • Anonymoose


      • Haulin’ Oats

        Why do we need a wildcat for this purpose when there’s a ton of ready and
        available commercial solutions to this problem.

        No one ever said an AR-15 is the only way to hunt pigs.

        • The Tin Star Kid

          Because ‘Merica…and why not?

      • Steve T. Wilson

        Kelly, AR-10?

  • ExMachina1

    Woke up to an AR deluge this morning. Five of the 6 most-recent gun posts on TFB feature ARs. Maybe mix it up a bit?

    • Yup

      Its constantly Ar this, Glock accessory that.

      • AK™

        Crazy how nature do that,considering the 2 most common semi autos are AR-15 (Sportsmen,Police,Military,Competition) and Glock..(same as before)
        Its like theres a big market for those 2 or something..

    • noob

      It’s like the chevy small block of rifles

  • Basing it on a ~0.411″ projectile would have made more sense. Then you’d have a wider range of projectile weights spanning from the .41 Magnum to the .400 Holland & Holland.

    • noob

      Being a wildcat means a .41 could yet be derived if someone figures it out

    • Wolf

      .41 mag bullets are more likely to have feeding issues compared to. 400 bullets that are designed for autoloader use.

      • It depends. I suspect that some of the problems seen with the .41 Action Express were due to converting legacy 9x19mm handguns. These simply had not been designed around the .41 AE or the subsequent .40 S&W. Moreover, some early batches of .41 AE cartridges and cases were badly out of spec.

  • Anthony Commo

    Do you love 10mm bullets, but 10mm Auto just isn’t enough? Do you refer to .40S&W as short and weak? Well we’ve go the cartridge for you. Introducing the .40 Long & Strong! Now with with even more power! Call with in the next five minutes and we’ll include a free DVD guide to becoming the kind of douche-bag who only shoots wildcats. But wait there’s more! If you call within the next three minutes we’ll include a free .40 Long & Strong hat with our logo “I like it long and strong” embroidered on the front for all of your friends to see! All at the low, low price of your dignity. Call now, supplies are limited.

    • Beju

      Oh myyy…

    • Taco Tandoori
    • lucusloc

      Hey! I resemble that remark. Can I get my hat now?

    • Seth Hill

      Walk around saying “Cause I’m long, and I’m strong. And I’m down to get the shootin on.”

      • The Tin Star Kid

        I like shooting hogs and I cannot lie…

    • ozzallos .

      Internet fudds don’t want you to know about this super secret new caliber! Click here to learn more!

    • Wild Bill

      Sounds like somebody doesn’t know how to reload their own ammo. It’s still damm funny rant.

  • Veteran for Trump

    So many different calibers!
    When does someone develop the 17HMR AR? Or have they?

    • Taco Tandoori
    • Anonymoose

      And Franklin Armory has a .17 WSM AR.

      • Veteran for Trump

        So what is the difference between a .17HMR and the .17WSM?

        • ostiariusalpha

          About 650ft/s and 200 joules of energy that the .17 WSM has over the HMR with a 20gr bullet.

    • Holdfast_II

      In CT rimfire guns are allowed one more “evil feature” than center-fire guns, so one can actually sell an AR in rimfire . . .

      Hold the phone – could somebody please make a rimfire .300BLK cartridge?

      • Marcus D.

        There are such a thing as featureless ARs that are legal in California–even after the recent Bullet Button ban. Fixed/pinned stock, no pistol grip (but if you can’t wrap your thumb around it, its not a pistol grip), and no flash hider (but brakes are legal), and no vertical forward grip, and we are good to go. In this configuration, it doesn’t have to have a fixed mag either. Or you just buy a Mini14.

        • art frewin

          get rid of your politicians…

          • Marcus D.

            We’ve tried that with term limits. But they are like hogs in Texas….they breed faster that we can get rid of them.

          • art frewin

            don’t give up and keep trying. it appears that gun owners are increasing. paranoid people will be decreasing. keep working on it and i will hope for your success.

      • art frewin

        it is easier to make a politician in your own image. throw these pieces of crap out. the US is becoming more and more communistic every year. we know it does not work in reality.

  • kzrkp

    even if it’s not for me and i can’t see the practicality I do like hearing about new wildcats, they’re interesting

  • Vitor Roma

    Load lehigh 140gr extreme penetrator in those and have fun.

    • miniguyvegas

      At those velocities I’d rather use the extreme defender. I’d be concerned with the function of JHP or other standard pistol 40 bullets at greater than 3x velocity, maybe it frags, I’d love to see it in gel, not that it matters, but I can’t watch it in hogs.

  • Edeco

    I have a little fascination with fast, low SD projectiles. It’s the opposite of a lot if prevaling doctrines and that’s fine, but the results on gel, melons etc can be spectacular.

    • noob

      Sbr it and use it with a 60rd drum for cqb. Devastating.

  • Paul White


    Can we stop with the weird assed cartridges?

    • Duray

      Yeah, and what’s with people constantly designing new cars??? Every year, ANOTHER round of car shows with new concepts.

      • Paul White

        This is more akin to designing a new type of gasoline, that isn’t compatible with most cars, and offers minimal if any real world advantages.

        If there’s a new caliber I want it to do something markedly better than what we’ve got now. I’m not seeing that here.

        • Duray

          Why do you care if someone else wants to tinker and experiment? How on earth does it affect you?

          • gusto

            if ammo makers were focusing on less amount of calibres
            prices would drop for the most common ones 😛

    • TheNotoriousIUD

      I say let people experiment. Sure, 90% of them will come to nothing but they might do something interesting eventually. Besides, its no skin off my sack.

      • Random Disabled Person

        Don’t forget that wildcat cartridges gives Ammo Collectors “that elusive Item” to have for their collection. No collection can be complete without every variations of that case, and/or bullet size.

        My guess is most wildcats are created and used by people who are in reloading near the upper skill set level. Where creating something is part of its reward, with greater self satisfaction if it catches on.

        I wonder Pre-internet, how many wildcat cartridges were created flourished and then linger before disappearing? Only to be created in different region of the country(or world) and cycle the same fate.

        The one upside on reading old gun magazines is seeing the wildcat cartridges debates and knowing the historical outcomes. Makes these debates a little funnier with not cost or skin off our backs.

        • TheNotoriousIUD

          Very true.
          I dated a girl in high school who’s father used to be a safari guide in Africa then moved to Texas. He wrote for American Rifleman for years and was an expert on all kinds of weird cartridges.

  • Brett baker

    I like It! 135’s at 3000 is great for us whose hogs have ground in their name.

    • lucusloc

      And no cleanup necessary! Just turns them into a pink mist.

    • noob

      Does anyone sell a teflon .40 to .223 sabot? Asking for purely um educational reasons…

    • LilWolfy

      Energy drops extremely fast, so by the time you hit 150yds, you’re down to 838ft-lbs with a 135gr .40 cal Cor-Bon. .223 from a 14.5″ barrel has more energy at 150yds with a 77gr TMK. The numbers even at shorter distances are pretty sad.

  • Taco Tandoori

    I’m trying to wrap my head abound this one. The vast majority of .400 diameter bullets, hollowpoints in particular start fragmenting and losing structural integrity around 1400fps. Now a truncated flat nose or wide flatnose could be useful for hunting. This cartridge is really a mess. Especially when you can just buy .450 Bushmaster or .458 SOCOM and have components, dies, projectiles, powders already proven to work. Not to mention firearms that work with these cartridges.

    • Jared Vynn

      Well if you already are reloading for 10mm/40 short-and-weak you can at least share bullets with this. It’s why I am seriously considering getting a 450 Bushmaster as I could use my 45 acp bullets with it.

      • Raptor Fred

        The 450 bushmaster is a great cartridge for what it is. And really starts shining with handloads in a bolt action. The Ruger American is a great set up in this chambering.

        • Jared Vynn

          I’m torn between the Ruger American or an ar15 in 450 Bushmaster.

          • Raptor Fred

            The American is great, I can run loads that would damage an AR-15. CDI makes AICS 308 mag compatible bottom metal for either the factory stock or Boyds. Ruger or Magpul 308 mags. And all together it’s cheaper than an upper. (Pic for reference) The 450 Scout runs 308 mags. And you can too in the American. https://uploads.disquscdn.com/images/8bf873d13d094f7a416db466d88f09ba99c835c54786b6dfe8feac2e25ccf909.jpg

          • Jared Vynn

            I’ve been toying with the idea of getting an RAR and putting it in a MDT chassis. Theoretically I could get under 6.6 lbs loaded that way.

          • Raptor Fred

            I saw a guy in a forum running that exact set up in 450. Those stocks are great.

          • Jared Vynn

            I’ve been strongly tempted to use one for a “pistol” build in 300 blackout using a Howa mini barreled action.

          • Raptor Fred

            Haha how funny, I had the same idea with a 6.5 Grendel with the actions from Brownells.

          • Jared Vynn

            I contemplated 6.5 Grendel, but 300 blackout shares powder with other cartridges I reload for. Course I could always do both.

            And Brownells is also where I was looking.

          • Raptor Fred

            The 6.5g has very good ballistics from short barrels.

            7.5 Bartlien at 100 Yards. Groups averaged 1.5 Inches 2000 FPS 123 Match King
            8.5 Bartlien at 100 Yards. Groups Averaged 1.4 Inches 2100 FPS 123 Match King
            10.5 Bartlien at 100 Yards. Groups averaged .9 Inches 2200 FPS 123 Match King
            12.5 Lilja Blank Chambered by PF at 100 Yards. Groups .75 2300 FPS 123 Match King
            14.5 Lilja Blank Chambered by PF at 100 Yards. Groups .5 2350 FPS 123 Match King
            14.5 Krieger at 100 Yards. Groups averaged .38 2375 FPS 123 MatchKing

            Alexander Arms 12.5 inch 6.5mm Grendel
            Alexander Arms 100 grain Berger OTM 2470
            Alexander Arms 123 grain Scenar OTM 2330

          • art frewin

            it has to be an ar for me. maybe later i might consider a bolt action.

      • Paul White

        I’m interested in 450 but not until ammo’s more available and cheaper; it seems to frequently be unavailalbe at my regular online ammo places, let alone on store shelves

      • retrocon

        Well, i was already reloading for .50BMG and .45ACP, so i thought, “I really want to get into this wildcatting craze for the AR-15.”

        Still trying to get someone to cut me a chamber, but this is what i came up with. What the hell… always room for another AR caliber, right?

        It’s a 750 grain .50bmg on top of a .45acp, flared case. Haven’t figured out how to get the bullet through the chamber, yet, but hey, can’t be any tougher than coming up with a large caliber that will double stack, right? Terminal ballistics are perfect for annoying hogs… out of a test piece of 1/2″ iron pipe, i got 112 fps with 5.6 grains of 231 and a large pistol primer. Added bonus, you can measure the velocity with a baseball radar system.


    • lucusloc

      But you see, none of those other cartridges will doublestack in a standard mag. That totally justifies a new cartridge.

      • Raptor Fred

        Yea well, show me a functioning AR-15 chambered in this cartridge.

        • lucusloc

          Well hot damn, aren’t you picky. I bet you want your carry gun to be reliable as well, instead of chambering it in the new wildcat hotness. Some people just cannot be pleased. . .

          • Jared Vynn

            Hey I have a carry in a newish wildcat offering that is reliable. I sometimes carry a doublestack 1911 commander in 22tcm. Many jimmies have been rustled by it.

          • billjohnso20

            I love the 22TCM cartridge! If the bullet doesn’t get them, the fireball will!! The convertible RIA I own is incredible too!

    • Giolli Joker

      Lehigh solid bullets.

    • Cal S.

      What composition are these bullets you speak of? Liberty Defense offers 9mm and .40S&W copper bullets with enough powder behind them to pump them out at 2,000fps. The shooting reviews I’ve seen (they reached around the high 1900s due to barrel length) punched clean holes in the target.

      • Raptor Fred


        • Cal S.

          Odd. I was expecting some sources or something to back up your assertion. Regardless, it’s completely true. 100% copper .40S&W bullets can be propelled at 2000fps without shattering out of the barrel. Considering copper is significantly less dense than lead (most other jacketed bullets), then I doubt that a mere 2000fps would spell the doom of a copper-lead composition bullet either.

          However, I’ve never been one to disbelieve the results of actual tests that disprove my opinions. Baseless assertions? Everyday. Actual experimentation? No.

          • Raptor Fred

            A 60gr .400 diameter projectile has a sectional density of .053. Even if the constriction is monolithic copper, the bullet will shed velocity so quickly and penetrate so poorly past 50yds that it is completely unsuitable for hunting anything. On the other hand It is widely documented that most .40 caliber defensive use projectiles when pushed over the designed velocity envelope fail to perform as designed. Shorter penetration, excessive expansion resulting in jacket fragmentation/ separation. None of these characteristics are wanted in a handgun velocity projectile. Here’ s a pic of a 165gr Gold Dot with the bonded electroplated jacket separated from the core. https://uploads.disquscdn.com/images/fdbed84e20cc5e2bf520b81ea915c02018497f85bab3abf202d2bd7318cb97ca.jpg

          • Cal S.

            I see. I misunderstood, my bad. I’m sure you’re right, and you’ve put your finger on the fallacy of using bullets designed for handgun loads for something bigger. But, give it a shot (literally) and I’m certain they can figure out how to design a bullet that will work like a charm. It’s not the diameter, it’s the design.

          • ostiariusalpha

            Not out of the barrel, in the target. Lead has negligible elastic yield strength compared to copper, that thin copper jacket is all that’s keeping it together, so when it hits its target, that jackets going to peel clear off in the first inch and the lead is going to rapidly fragment to create a relatively shallow crater wound. Even at slightly lower than 2300ft/s velocities, using copper-jacketed HPs designed for 1400ft/s makes the bullet expand too fast, leaving you with greatly reduced pentration.

          • Cal S.

            Yes, but that’s not intrinsic to the diameter/caliber, it’s intrinsic to existing bullet designs. Just like the difference between M193 and M855A1 in 5.56NATO, they’ll have to re-engineer projectiles to work with higher velocities. I mean, they figured it out for 10mm.

            Disappointing handloaders, I’m sure, who would like to use their favorite handgun bullets.

    • S. Plankenberg

      Nothing but a future Unsuccessful Cartridge Designs trivia question.

      If you need a high-capacity magazine to hunt ANYTHING, your marksmanship and /or methods suck.

      • Don’tBASucker

        it’s not about poor shooting ability, it’s about using a gun that ‘can’ be used for WROL during the time when there is peace

        • S. Plankenberg

          What is WROL?

          • Don’tBASucker

            With Rule Of Law

    • cawpin

      “Especially when you can just buy .450 Bushmaster or .458 SOCOM and have components, dies, projectiles, powders already proven to work. Not to mention firearms that work with these cartridges.”

      Agreed. Although, I greatly prefer the Socom because the Bushmaster is still limited by handgun bullets.

  • Klaus Von Schmitto

    Looks to me that .358 MGP has better numbers and a lot more options on bullets.

  • TexianPatriot

    I’m not against wildcat rounds, but if you spent the time you spent developing this round practicing marksmanship, you would not need a new special cartridge to kill pigs.
    5.56 works fine. So does 300 blackout, 6.5, 6.8, etc.
    If you are a bad shot and need bigger, they have that too, .50, .458, .450 etc.
    These are just the AR.

    • john huscio

      Innovation never sleeps

    • lucusloc

      Typically if you are developing a wildcat you already shoot quite a bit. Unless you are doing it just for fun the idea of a new wildcat is to see if it can gain traction and become a commercial success. There are quite a few big bore AR cartridges already, but who knows, maybe this one will have that special something that it needs to gains widespread popularity.

  • Scott Tuttle

    ohhh damn, that was close, I was just about to order a 300 blackout barrel!

  • valorius

    I guess its an optical illusion, but judging by the photo those cartridges look way too long for an AR magazine.

  • JGS

    “135 gr bullets at 3,042 fps”

    These numbers seem off to me. Getting 556 velocities with double the projectile mass?

  • Jeremy

    ” The Carcano case has head (.447″) dimensions identical to that of 7.62x39mm cartridge, which means that they could use 7.62x39mm or 6.5mm Grendel bolts.”
    No, the 7.62x39mm and 6.5 Grendel bolts headspace differently as the bolt face on the Grendel was moved forward slightly.

  • gusto

    or just buy a ar10 in 308win and be happy?

    or even better buy a browning BLR and be even happier because you are carrying a slim and very pointable rifle

    btw what you shouldn not do is hunt hogs with 223/556. don’t care that hogs are considered a pest, use a proper calibre for the job

    • Marcus D.

      .223 has taken plenty of hogs. The real issue is the right projectile, not the caliber. Lehigh for one makes a rather wicked HP round for game.

      • Mazryonh

        Are you sure the hog problem isn’t something that can be solved with more manpower and know-how rather than firepower? Lots of hogs were killed in the pre-gunpowder days by people with dogs, horses, arrows, spears, or even swords, plus a lot of courage and knowledge–no guns required.

        • Marcus D.

          those people using dogs, arrows and spears were the nobility and owned all the lands, allowing them to go hither thither and yon in pursuit of prey. Private property owners today have the right to exclude others, and charge–handsomely it would seem–for the privilege of hunting on their lands. It is so lucrative it appears that some owners actually stock hogs. Add to the issue is that the natural predators such as wolves are gone, and the only large predators are men. Until Texas declares hogs a nuisance and orders bounties, the hogs’ scourge will continue if not increase.

          • Mazryonh

            Even we can’t round up “all the king’s horses and all the king’s men” anymore to stamp out the agricultural menace that feral hogs have become, why isn’t the government already offering bigger incentives for more hunters to bring down what the hog traps can’t?

            The government could also step in and say that “stocking” hogs is illegal since it means they’re free to breed and repopulate, which is counterproductive. Maybe it’s time to “sound the horns” and bring in enough manpower to put the problem down for good. Even a bunch of people with muzzleloaders could do the trick if there were enough of them, and donating unused meat to charity would be a good use of the unwanted hogs.

            As for charging too much for the privilege of hunting on private land, we’re dealing with an invasive agricultural pest that doesn’t respect borders and causes lots of damage anywhere it can find food. Sounds like the laws regarding this could be changed for the better.

    • Philthegardner

      I use surplus green tips. It’s not the caliber but where you put it. In South Texas, heavy brush means I never take shots more than a hundred yards. Armor piercing for the thick armor on their heads. Anywhere from the eyeball to the ear from the side or the general area between the eyes when shooting head-on. They drop like a rock. But worst case scenario is a shot to the upper neck behind the ears to sever the spine. Drops em quick. But I prefer high head shots.

  • Glenn Waltman

    Love my Big Bore AR in 458 Socom,So many bullet options and so many different load combinations.

  • Cal S.

    Imagine putting a 60gr Liberty Defense bullet on top of all this powder…

    • Jared Vynn

      Or one of the ARX. Probably would need a different twist rate though.

      • Cal S.

        I think at some point it would be impossible to achieve stability of any kind with such light bullets, lol.

  • JoshuaK27

    Hrachya,jyst wanna say glad to have you with t.f.b I forgot to say this a long time ago .

  • Mark Horning

    Pretty sure that if I wanted a dedicated hog gun on an AR platform I would just build a .458 SOCOM rather than this oddball.

  • Christopher Wallace

    if you already load for 10mm and have an ar, this is pretty intriguing. I imagine it would absolutely wreck hogs and deer, esp when you know how well a 200gr xtp moving around 1300fps makes deer dead.

    • Mazryonh

      Assuming you load it to maximum effective weight and maximum velocity, the only really effective 10mm bullets you could use would be non-hollowpoint ones with wide flat nose for maximum penetration and energy retention at a better distance than with 10mm Auto rounds, since the diameter of the bullet means its ballistic coefficient isn’t very good (in other words its drag is a bit high even with the high bullet weight).

  • Brandon Hurst

    Sounds like an american version of the 9×39.

    • Mazryonh

      Seeing long, heavy subsonic bullets in this 10x43mm caliber would be very interesting.

  • Cal S.

    Gotcha. I’m just so used to everyone hating on the .40cal because it’s popular to do so that I mistook your premise.

    Yep, that might do it. Hornady did something very similar with their ‘Leverevolution’ line of revolver loads to compensate for shortcomings of existing bullets at the higher velocities achieved by lever guns for .38 spl on up to .44 mag, I believe. They seem to work!

  • ElevenBravo

    I am very interested, however my Google Fu is weak.. I cant find a video or good writeup on this. As of now. Maybe never?

    • Mazryonh

      As of the date of this blog entry, the wordpress website dedicated to this wildcat round is still under construction.

  • Mazryonh

    I can see how this wildcat might get some interest from the 10mm crowd who want to put even more juice (case capacity) behind their .40 caliber bullets, while still being able to handload the same bullets into the shorter 10mm Auto cases for handguns/pistol caliber carbines.

    However, since .40 caliber bullets don’t have anywhere near an optimal ballistic coefficient due to their short and relatively wide shapes, some of that extra case capacity in this .400AR wildcat will likely go to waste just to overcome drag after the bullet leaves the muzzle. It also means that the effective ranges for these rounds are probably going to be shorter than expected for a rifle-sized caliber with that much case capacity behind it, because the drag means it will lose velocity more quickly than most commonly-used rifle rounds.

    At closer ranges, 10mm Auto hollowpoints that work well out of handguns or PCCs are likely to have too much velocity when loaded into this wildcat to expand at their intended depths, and will just fragment to produce shallow “splash” wounds. On the other hand, if used at relatively short ranges (for a rifle round) and loaded with non-expanding ammunition that has a good flat nose, you’d get the same barrier-blindness and anti-windshield capabilities that full-power 10mm Auto is known for, just at an increased effective range.

    The above concerns wouldn’t be too difficult to address with new 10mm projectiles made for this case, however. With all the room available, you’d be able to make a true 10mm rifle projectile, with the standard spitzer tip and boat-tail to reduce drag and increase sectional density for possible military applications. If the .400AR design team goes down this route to develop the full potential of this caliber, the results will probably be the most interesting developments of this wildcat. Even without making new projectiles, this looks all-in-all like a promising attempt to realize Jeff Cooper’s “Thumper” rifle concept, but with more magazine capacity than previous attempts like the .450 Bushmaster or .458 SOCOM cartridges.

  • frrst245

    isn’t this a recreation of the 401wsl that uses bullets not optimized for their velocities?

  • Nonya Bidness

    Sounds good in theory and the numbers are impressive but there is a distinct shortage of 10mm bullets capable of living at those velocities. The 135gr reference is nothing short of a joke because they come completely unglued at 1600fps. None of the existing 180-200gr jacketed bullets will do much better and at these velocities, you’re really pushing the limit of a cast bullet. What is needed is a good 220-250gr solid copper or controlled expansion jacketed bullet. The former would still be useful in handguns, the latter, not so much.

  • Cole Dedhand

    Another me-too AR wildcat that does nothing better than commercial loadings. Yawn.

  • art frewin

    what you say has a lot of merit, but how far did that chunk of lead travel with the gold dot. i understand there is a limit at which complete destruction takes place, but the best one shot stop statistics was the 357 mag with a 125 gr hollow point bullet. i believe that was due to the fragmentation of the hollow point bullet and the lead lower continuing through the media. so there is a point which the bullet comes a part but is not a total destruction like a small grain bullet out of a 22 250, going over 4000 fps. if there is a big enough lead chunk it would seem to me that it would deform but continue penetrating. i can hardly wait to do some water trials on some of these just to see what happens.

  • Robert Kalani Foxworthy

    so they made a 10mm magnum case slightly longer but use the slight tapper like a 44 auto mag.

  • Cal S.

    Hey, well, that’s good to hear! I too love .40, as much for what it can as well as because it’s so hated. I’m the same way, relatively non-domatic about calibers.

    That’s interesting. Maybe you could make a new cartridge: like .38 special short or something, lol.

  • Patrick Walls

    I would like to see an AR15 in 357 Maximum !

  • jonp

    I’m still wondering about the justification of this cartridge outside of it’s a wildcat and more choices are better. What does it do better than the 450 Bushmaster? Do you really need a double stack mag if your hog hunting? How many .40 Cal bullets are out there that can be pushed to the 2,000fps+ velocity and remain intact and functioning as designed?

    • Mazryonh

      You could stick with solid non-expanding bullets to start. If there’s enough interest, someone could probably make an expanding soft-point for this wildcat. But you’re right in the sense that it would take a new .40 caliber projectile, likely a more rifle-like one with a spitzer tip and a boat tail, to take full advantage of this new case.

      As for its double-stack capability, some people like more chances in their box magazines, or need to put down as many members of a herd of feral hogs before they all scatter into the brush. Even shots from a suppressed firearm or well-placed arrows/bolts don’t do anything for the scream of pain from a hog that’s been hit, or the sound of it flopping on the ground, which can send the rest of the herd running for cover.

  • Rogertc1

    My Bewolf 50 is still bigger.

  • Tony

    That’s not going to work as advertised. The forward ribs on each side of a standard magazine are going to pinch the front of the rounds inward and disrupt the stack. You’ll only be able to double stack 8 or so rounds before the stack is so screwed up, it no longer feeds.

  • Zobeid

    Or else, you could just get an AR-10??

  • Nonya Bidness

    Of course ammo is not easy, it’s a friggin’ wildcat. It’s also being developed by individuals, not a company, so it’s not a “proprietary cartridge”. You obviously don’t know what these terms mean so I have to question your “in depth analysis”.

    Energy is about the poorest measure of a cartridge’s effectiveness. It places far too much importance on velocity, too little on mass and zero on diameter. Look at all the handgun rounds that produce significantly less energy than your .308 but have been used effectively against all dangerous game in the world. Sorry but energy is not a useful number.

    And the .400AR fits into a standard AR-15. The .308 is restricted to the AR-10 sized platforms. The .400 is also a better solution for subsonic/suppressed use.

  • JamesDrouin

    Wildcat rounds always have a difficult birth and most are short-lived. This one has doubled down on the obstacles it will face.

  • Guido FL

    Hog hunting with a AR issues are solved using 7.62×39 uppers, bolt carriers, & C-Products mags. Cheap Russian [ .20 per rd. ] ammo for practice and US made soft points for killing hogs. One shot on kill, time and again in South FL.

  • billjohnso20

    I am always interested in wildcat loads. There was a time when our standard ammunition options were all wildcats. As there are some who liked this idea and some who hate the idea, so it was with the .357 Magnum, 44 Magnum, .270 Remington, 300 Whisper/300 Blackout etc. I will be following this one because I’m interested in what the final adopted product will be.

  • Don’tBASucker

    all for something new, but 300 blackout already has the ‘hog killin’ role locked up
    heavy copper 223 round are good enough if you know where to put the pill

    400AR ? ….solution in search of a problem

  • chuckles

    If I were going hog hunting and felt the AR15 just lacked the horsepower for a 300lb sow, I would just move my hand a few inches to the right and grab my AR10 in .308. I love wildcats but eventually you have to make the case why I need one. This article lacks that. Maybe getting this round in a revolver? Who knows? I might see this in TC Contender, but that’s just me. I love my Contenders but if I’m hog hunting, I want multiple rounds available.

  • Lloyd Esp


  • disqus_1IXWD6GbBr

    And yet another AR-something-caliber rifle?

    B O A R I N G!