Re: Need some help..... fast
20" upper and carbine stock/buffer/tube should have absolutely nothing to do with it at all. I have seen plenty of rifle-length gas systems running with carbine stock setups with no problems and I currently run a few myself.
I tend to agree with nut job that it might be a short stroking situation. Short stroking is when the bolt carrier group does not cycle far enough to the rear to be able to strip a round from the magazine and chamber the next round. It varies in degrees and can either cause a stove pipe of the ejecting round, a complete ejection and failure to pick up a new round causing the bolt to close on an empty chamber, or, sometimes you can get a short stroke similar to what you are describing.
This happens when there is an issue with the gas system.
To see if you have a short stroking problem and not another problem, try the following:
1) Insert one round into a magazine that you know to be performing well;
2) Insert the magazine into the magazine well, pull the charging handle to the rear, then release the charging handle to chamber the round;
3) Discharge that round;
4) After the round has been fired the bolt should automatically be locked to the rear by the bolt catch and the empty magazine. If the bolt is closed on the empty chamber, then it did not travel far enough to the rear to be held by the bolt catch, and your rifle has short stroked.
If you are having a short stroking problem, is it one or more of several problems. Check the following:
1) Ammo: Some commercial ammo is not be strong enough to cycle an AR. Swicth ammos and see if that resolves the issue. If the weapon works correctly then you may have some bad ammo.
2) Lube and clean: Properly clean and lube the rifle per spec.
3) Carrier key: If the carrier key is loose, the gas system will not hold enough pressure to fully cycle the weapon. If it is loose, torqued the bolts down to 35-40 in/lbs (and I'd stake the darn thing if not done already which should prevent it from coming lose to a certain extent).
4) Gas tube: Inspect your gas tube and determine if there is any visible damage. If so, replace it. If not, you may try cleaning it and see if there is some form of obstruction or other problem.
5) Gas rings: Inspect the rings and make sure that they are installed properly. Disassemble the carrier group, clean and inspect for any signs of trouble/damage, and again, if you haven't already, properly lube everything before it goes back in rifle.
If none of that works...well...prayer may help!!!
Seriously, try that and see what happens. If not, come back and the folks her can try again.
Thx to THR for info above on SS.
