Eyewall Industries have developed simple but useful device they called the STOKBLOK. What is does is prevent an M4-style adjustable stock from extending further than a desired distance and so preventing accidentally extending is to far when under stress. It seems like a very good idea for anyone who is forced to store their AR-15 with the stock collapsed.

Brownells are selling the STOKBLOK for $10.

UPDATE: The STOKBLOK is also compatible with the new Colt Superstoc. Eyewall Industries asked me to mention that the STOKBLOK is patent pending.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Lance

    Looks good wonder if new Colt stocks will have a similar device?

  • That is a wonderful idea.
    Simple and fixes a problem that’s annoyed the hell out of us at one time or another.
    Inexpensive too.

  • Maigo

    Wow, duh. Why didn’t Magpul start putting these things out years ago?

  • fw226

    What a shockingly simple solution.

  • C3PO

    Umm, Anyone ever heard of a set screw?, that would set the stop distance just as well, and cost about half of what this would, I also don’t see how this is going to stay in, but it looks like a press fit. This would be okay if it wasn’t receiving cartridge recoil impulses repeatedly. . . what happens if it falls out? it falls into the stock adjustment mechanism? thread locker (Loctite) would fix that, but then again, so would a set screw. . .which also would take some thread locker if you’re worried about it falling out

    • Eyewall Industries

      It is not a press fit (or a permanent modification), nor does it receive any recoil impulse. It drops in and the buttstock retains it from falling out. The recoil pin in the buttstock still connects to the buffer tube/receiver extension as it always has. The STOKBLOK simply eliminates the ability for the stock to retract further than desired.

  • Bryan S.

    Wonder if this counts as a lock for those who are not allowed to have adjustable stocks.

  • Alan

    Designed by an engineer whose keyboard was missing a letter, the Stok Blok is a first-line defense against aidental stok ollapse for your Olt AR-15/M4 Arbine.

    • Matt G.

      Lol. I see what you did there.

    • Eyewall Industries

      Our budget only allowed for eight letters. We felt that STOKBLOK sounded better than STOCKBLO.

  • Ric

    There are a lot of little things that get designed and manufactured for the soul purpose separating gun owners from their money. This actually seems to fill a need.

    I like the idea of having as many stops as possible in my stock, but once you know where your stock needs to be this item really starts to make sense.

  • thebronze

    This is an EXCELLENT solution to a practically non-existent problem!