Maximum Pressure For Straight Blowback Firearm?

[lucusloc]

The Oerlikon 20mm AA cannons are straight blowback. Might work in an AR platform, but you'd need one heck of a recoil

I got interested in the Oerlikons after visiting Pearl Harbor. The mechanism is a bit more complex than a normal straight blowback system. The firing pin ignites the cartridge while the bolt is still moving forward, so the pressure has to overcome the inertia of the bolt as well as the weight. Still a heavy bolt, but no where near 200lbs. The whole gun weights about 200lbs unloaded.

The Brits used a system of pulleys to cock the action. The American mounts had a bar that hooked in the bolt know, then the operator tilted the gun up using their body weight.

That sounds like an incredibly interesting system, and a genius way to multiply inertia by converting it from static inertia to opposed inertia. I wonder how tolerant it is of timing, and if it would be viable in a smaller package...

 

[Benchrest]

Lock time, what you seek is lock time.