F&D Tactical’s SHUT – The Anti Accu-Wedge

AR-15 shooters have long had to contend with “receiver wobble.” While never detrimental to the function of the firearm, the wobble has been a constant source of annoyance for AR lovers from the firearms world where solid feel is often put on a pedestal. Various solutions have been offered for this including milling receivers to extremely tight tolerances (which loosen over time), to tensioning screws, to the Accu-Wedge, all of which worked to eliminate the wobble. Almost every solution has been focused on pushing the upper receiver upwards at the rear, which in rare extreme cases can create a significant gap enough for debris to enter the receiver.

F&D Defense has looked at it from another perspective, instead opting to put managed pressure on the front of the receiver and pull it back downwards using the rear pin. Called the “SHUT” feature which stands for Solid Hinge Upper Receiver. In short, they add a small hump on the front of the receiver which puts the upper in slight tension when the takedown pin installed, removing slack.

The SHUT feature is listed as patent-pending and sadly, no word on the upcoming availability or pricing or the lower receiver. Fortunately, the tech will be applied to standard forged lowers, so builders will have a myriad of options to match their F&D SHUT lower.

Head on over to F&D Defense for the full briefing video. 

Nathan S

One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

The above post is my opinion and does not reflect the views of any company or organization.


  • Juggernaut

    JB Weld the upper and lower together for a wobble-free fit.

    • Nicks87

      Please, nobody do this. Just buy a rifle from a reputable company or build one with quality parts.

      • Phillip Cooper

        Actually, if you want to remove the slop, it’s simple.. do what Juggernaut said, EXCEPT- wax the upper first in the contact area of the JB Weld so it won’t stick.

        Works like a champ.

    • mazkact

      The US Army marksmanship unit beds their uppers to the lowers. I do not think they use JB Weld but it is a similar product. After this bedding is done the upper must be pulled up and not hinged to remove it. I’ve done three in this manner. The mating surface of the upper is scuffed then Belzona metal epoxy is applied. The lower is greased thoroughly, a piece of closed cell foam(or an accuwedge) is placed under the lug to create as much space a possible. The halves are put together and allowed to cure overnight. In the morning a little prayer is said and then the pins are removed and the upper comes out vertically. I find this method to be helpful for match or bench guns. Those fellows at the marksmanship unit do know a thing or two about good shooting rifles.

  • Kyle

    I swear I just read this exact article here a few days ago….

    • Kyle

      Everyday is re-post day! Never minded the slight receiver wobble and I’ve never seen an AR with enough wobble to consider a problem.

      • Nicks87

        This^. If receiver wobble is a big concern (it’s not) maybe buy a matched upper and lower or just buy a better quality rifle with less wobble. I swear people just create “issues” just so they have something to complain about.

  • A.WChuck

    Someone reallly needs to start managing this blog. This is a repeat from April 11 article by Hrachya H. If I can search for this, so can the authors before posting.

    • DanGoodShot

      Yeah, and this is not the first time I’ve seen this happen either. I’ve also seen articles asking about stuff that another auther already addressed. I’m really starting wounder about inter tfb communication. Or the lack there of.

    • Scott Wagner

      It’s not even a matter of searching. It’s a matter of reading your own damned blog. They have apparently zero content control or editing anymore.

      • JumpIf NotZero

        I’ll give you that mistakes happen, but man it’s worse when the product was so dumb it probably shouldn’t have even had a first post let alone a second.

        • AHill

          I agree mistakes do happen but if memory serves this is not the first or even second time this has happened. Also with such a dumb product that shouldn’t have even had article done I also agree, it might be conspiracy minded but a small speck of suspicion makes me wonder if this was paid advertising (not a 100% conclusion but there is some suspicion). I just have to say that I am very disappointed in TFB; it really hurts your brand and credibility when it looks like you have no communication or over sight. If you want to be taken seriously and professional; you must first take yourself seriously and act professional.

          On the “wobbly” receiver fit, just buy one of those accuwedge things if it bothers your so much, not some out of spec ugly lower. (I don’t know if it affects grouping; but the accuwedge does remove the slop if there is any. I doubt I would purchase one for a build but getting the included one with my Colt Canada SA15.7 doesn’t hurt anything so it’ll stay there till it wears out I guess.)

          • JumpIf NotZero

            Yea IDK. Everyone is struggling to figure out how to monetize so nothing surprises me anymore.

          • Brian

            Wow thats some serious judgement and presumption that all fdel as you do about what i happen to think is a pretty neat product that has with innovation uniquely fixed an issue many suffer from and incorporated it into the manufacturing of the product instead of needing a person to buy a stupid peice of aftermarket plastic to fix the brand new AR they bought that is full of slop. Bravo neat idea!

  • TechnoTriticale

    Patent-free idea: mill a slot the top of the upper and wedge in an elastomer band.

    Eliminates rattle, but metal stays dimensionally in spec. Helps keep out dust too.

    • Nicks87

      Really? If receiver wobble is that big of a concern, maybe just buy a better quality AR15. The cost of the millwork could just be put towards a better rifle.

  • RSG

    Building an out of spec receiver wasn’t a good idea the first time TFB pushed this on us. Why persist? Or is it simply incompetence?

    • Lee Attiny

      Most top tier receivers on the market are built out of spec. Its called innovation

      • mazkact

        I find that Anderson lowers are just out of spec enough to make any upper a little hard to pin to it,I rather like that 🙂

  • Phillip Cooper

    I do the same thing with JB Weld for about $0.60. Or, I just don’t worry about a little rattle.

  • BravoSeven

    My AR didn’t wobble a week ago when the first article was posted and still doesn’t wobble now with the second post of the same damn article.

  • 22winmag

    Twice in one week with this article… and only 3 weeks late with the Glock lawsuit dismissal.

    Still, even with all the knife, flashlight, and grenade launcher reviews, TFB beats the crap out of most firearms blogs.

  • Gregory

    My IWI X95 has no wobble. Oh, wait, it’s not an AR so I’d does not count. It also does not crap where it eats. It also does not burn out it lubricant.

    • Joe

      It also does not work when muddy. So theres that.

      • Nicks87

        …and has terrible ergonomics, becomes inaccurate when it heats up, has an awful trigger and is a bullpup. But other than that the X95 is a great rifle lol.

        • Rick O’Shay

          “but other than that…” lol

    • Porty1119

      We shall not speak of the Tavor trigger. That thing is a miserable excuse for a rifleman’s weapon.

    • mosinman

      i guess you don’t own any blowback guns since you’re concerned about a gun that “craps” where it eats

  • displacer

    Or you could put a thin o-ring around the front receiver takedown hinge and get the exact same effect on any existing gun or set of receivers, for like 15 cents a pop

  • Raptor Fred


  • Klaus Von Schmitto

    And since the barrel and the optic is on the upper why does it matter again?

  • Fred Lin

    Why don’t just drill the pivot pin hole a bit lower…..? same effect but no extra cost : D

    The first AR15 brand who using this way to solve wobble problem I ever seen, is a Taiwanese Airsoft brand “Inokatsu” use this idea on their forged AR15 gas rifle : P