Open bolt assault rifle patent

by ImproGuns

Here is an interesting patent ( US4019423) for an open bolt assault rifle which looks like a cross between a STEN and an M16. A large compression spring is depicted in front of the barrel assembly which in theory will slightly delay the breech opening when struck by the bolt as a round is chambered. A very simple concept on paper, though I can see a hang-fire not being too pleasant.


The unconventional, improvised and modified firearms blog

More by ImproGuns

Join the conversation
2 of 29 comments
  • Cal S. Cal S. on Oct 08, 2015

    But does it have a tactical dust cover? I'll only buy it if it has a tactical dust cover. And rails.

    Awesome concept, simple too!

  • Tassiebush Tassiebush on Oct 08, 2015

    It would be really interesting to see a prototype built to see how this would actually work vs the theory and speculation. The VG1-5 works as a blowback with an intermediate length cartridge despite the intention it be gas delay blowback. This probably gets away with a lighter bolt due to it's advance primer ignition but the big question is whether the barrel movement further helps as intended?
    It sort of looks like it'd be a constant recoil design if it can handle the cartridge it takes.