AR Sponsor
Posted: 2/25/2007 2:53:46 PM EDT
|
stovepipe jam almost every time. sometimes it ejects but closes empty. tried different ammo, different lower, and different mags i think it might be the gas system but want your opinions. any thoughts? |
|
Upgrade the extractor spring tension. I recommend a Wolf extra power spring, black extractor spring buffer and a crane o-ring on the spring. I have a beater upper that I literally assembled with parts from the scrap bin. First trip out it was having all sorts of failure to extract/eject. Upgrading the extractor spring tension fixed everything and it ran perfect in a 3 gun match yesterday. |
If the bolt jumps the case rim of the chambred round, the bolt carrier loses momentum and then short strokes. The case will then be ejected from the chamber after the bullet leaves the bore by residual pressure in the barrel. Then the case gets caught up in the action. I suspect this is probably a carbine because rifles don't have this problem. If it's not doing funky things with cases and is always ejecting properly, then you have a gas leak or you are under-gassed. That's classic short stroking. Do the short stroke test. Fire a single round from a magazine. Do this ten times. It should lock back on the empty mag EVERY time. Also check freedom of carrier travel. Take the upper off the lower. Leave the carrier installed and charging handle latched into the receiver. Hold the receiver so that the muzzle is pointed 45 degrees DOWN. Withdraw the carrier all the way back until it stops against the latched charging handle. Release the carrier. It should go all the way to the bolt and you will hear a "ting" when it bounces. |
Look for gas leakage everywhere: Gas tube to gas block interface gas block to barrel interface around the gas tube at the gas key gas key to carrier interface (key loose or carrier/key not flat) missing all 3 gas rings |
if it is a set screw gas block they will come loosee repeatedly unless you use red loc-tite on the threads. and when they come loose all your gas leaks out rather than traveling back to the action.. I had this happen and it puzzled the hell out of alot of us until randall rausch remembered he forgot to loctite the thing when he mailed it back 
|
|
ok. still doing it. sometimes it stovepipes and sometimes it just closes on the empty case without ejecting it at all. i dont think the bolt is even coming back at all when that happens. the gas block is positioned and tight. the tube looks centered in the receiver. sometimes it is hard to pull the charge handle. the last shot does not hold the bolt open, but if you pull the charge handle it does lock every time. ?  ?
|
AR Sponsor