Let me discuss the issue first. I had a registered SBR lower sitting around doing nothing so I decided to put together a hog gun. I ordered a 10.5" 7.62x39 upper to use it suppressed. I already had a 16" AR15 in this cal., but it is long and unwieldy with the can on it while getting in and out of my UTV. When I went to test fire and site it in, it is doing something I have never experienced in an AR. After firing and the bolt returns to battery, there is a distinct horizontal wobble that lasts for a half second or so. You can feel it shaking on your shoulder and in you cheek. It doesn't do it every time, but most of the time. Once every few shots it just locks into battery like any normal AR solid and still. It seems like some sort of weird harmonic resonance. The lower has an A2 style fixed stock with the standard rifle buffer and tube. Possibly this has something to do with it, but I don't know why since I am not an AR expert. The upper has an adjustable gas block so I have reduced the gas to where it seems to be properly ejecting and returning to battery. You would think adjusting the gas would change any harmonics as the bolt cycle is changing speed. When it is wobbling, you can clearly hear the buffer spring boinging back and forth inside the tube. I don't know if this is the cause of the wobble or just a result from the gun shaking. This has no effect on bench accuracy punching paper, but a quick followup shot might be all over the place.
The question I have is has anyone ever seen a heavier than standard rifle buffer that would help slow down the bolt and maybe change the harmonics? I have done some searching and while lots of places have various weighted carbine buffers, no one has anything for a heavier rifle buffer.
The question I have is has anyone ever seen a heavier than standard rifle buffer that would help slow down the bolt and maybe change the harmonics? I have done some searching and while lots of places have various weighted carbine buffers, no one has anything for a heavier rifle buffer.
