someguy2800
Member
I have an AR15 that I've been playing with all summer. I built it from an anderson lower, a BCA side charging upper, APF parts kit, and a Leapers A2 rifle stock and buffer. I started with a mid length pencil16", then a heavy 20" rifle length, then a medium weight 16", and now I just got a real light weight Ballistic Advantage 20" fluted 223 wylde barrel that I put on today.
The gun has always been spotty with locking back on the last round but now with the BA barrel it short strokes so bad that with all but the hottest loads you have to cycle the bolt by hand with each round as it doesn't cycle far enough to pick up a round. I had some real light loads that would half cycle and rechamber the spent round. I took it apart and the gas block hole is centered over the gas port in the barrel and the hole in the gas tube is open into the gas block. The gas tube is not plugged, I can blow through it freely and stick a wire down it. Gas port in the barrel is .090". I just cleaned the action bolt and carrier and oiled them up good. The buffer tube and spring are greased. The bolt carrier moves freely and smoothly it's whole length of travel. Loads are warm, 1/2 grain under max and primers show healthy pressure. Factory ammo also works the same.
Today I experimented with the buffer. It's a rifle buffer so it's 5 oz and has 5 weights inside. I removed two weights and put a piece of rubber hose in there place of the same length, not much difference. Then I replaced one more weight and the aluminum spacer with a rubber hose and cut an inch off the buffer spring. Then it would cycle but not lock back. Finally I emptied the buffer completely and put it back together. It functions perfect now with an empty 1.7 oz buffer.
Is there something I'm missing in the gas system? Something to check in the bolt carrier? It's working fine now but it would be nice to get it working with the proper buffer weight and spring and have a bit more margin of reliability. This is a varmint gun, not a defense gun, so it's not that critical but it's annoying having to fiddle with it when shooting.
The gun has always been spotty with locking back on the last round but now with the BA barrel it short strokes so bad that with all but the hottest loads you have to cycle the bolt by hand with each round as it doesn't cycle far enough to pick up a round. I had some real light loads that would half cycle and rechamber the spent round. I took it apart and the gas block hole is centered over the gas port in the barrel and the hole in the gas tube is open into the gas block. The gas tube is not plugged, I can blow through it freely and stick a wire down it. Gas port in the barrel is .090". I just cleaned the action bolt and carrier and oiled them up good. The buffer tube and spring are greased. The bolt carrier moves freely and smoothly it's whole length of travel. Loads are warm, 1/2 grain under max and primers show healthy pressure. Factory ammo also works the same.
Today I experimented with the buffer. It's a rifle buffer so it's 5 oz and has 5 weights inside. I removed two weights and put a piece of rubber hose in there place of the same length, not much difference. Then I replaced one more weight and the aluminum spacer with a rubber hose and cut an inch off the buffer spring. Then it would cycle but not lock back. Finally I emptied the buffer completely and put it back together. It functions perfect now with an empty 1.7 oz buffer.
Is there something I'm missing in the gas system? Something to check in the bolt carrier? It's working fine now but it would be nice to get it working with the proper buffer weight and spring and have a bit more margin of reliability. This is a varmint gun, not a defense gun, so it's not that critical but it's annoying having to fiddle with it when shooting.