New AR-15 won't strip rounds

[bluehen59]

Just took my new AR to the range today, first round fine, then "click". It ejected the brass fine but did not strip another round out of the magazine. Every time I had to manually cycle it to strip another round. Someone there gave me some oil, I oiled the bolt and it worked ok for a little while then it would go back to not stripping a round after firing. A few times the bolt got stuck halfway after ejecting the brass. Any ideas?

[ScotsGuards]

Hummmm? A few questions. Was the rifle purchased compleat or did you build it from parts yourself? What manufacturer of rifle or parts? Did you do initial pre-operative maintainence before you fired it? What type of ammunition were you using? Did you try a different magazine(s)? Lots of variables there. Please give more details for assistance.

[G23neverjams]

that's completely true. what the previous poster said, there's too many variables. my STAG ar15 has never had a hiccup what so ever.

please let me know what type of AR you have and that will help to diagnose the problem..

PS, i'm an armorer in the US army and have extensive training with the AR15/ M16/ M4.....

[Ronnies111]

Just took my new AR to the range today, first round fine, then "click". It ejected the brass fine but did not strip another round out of the magazine. Every time I had to manually cycle it to strip another round. Someone there gave me some oil, I oiled the bolt and it worked ok for a little while then it would go back to not stripping a round after firing. A few times the bolt got stuck halfway after ejecting the brass. Any ideas?

Went to the range with No Oil...a no no..I just grab the break free & crudely spray well, the bolt & surrounding area every 100 rds or so. Better to lube to much than not enough. This will surely prevent premature wear.

[LittleRedToyota]

sounds like it is short-stroking to me. there are several possible causes.

not enough lube is certainly at the top of the list. ARs like to be wet.

obstructed/pinched/bent gas tube. out of spec gas port. loose gas key. wrong buffer for upper configuration. obstructed/out of spec buffer tube. buffer spring too stiff.

etc. etc. etc.

it could just be lack of lube coupled with needing to be broken in if it is brand new (especially if you are using underpowered ammo like UMC). try lubing it good and going back to the range and running some hot ammo through it.

see this google search for more:

http://www.google.com/search?sourcei...stroking+cause

[chauncey]

here's some stuff i would try:
1. a different magazine - preferably a Pmag
2. try different ammunition. Federal FMJ is the best, imo. avoid steel casings.
3. lubricate properly, and if that doesn't work, try a ridiculous amount of lubricant
4. clean the chamber with a solvent that doesn't leave any residue
5. clean the gas tube with a pipe cleaner and solvent that doesn't allow any residue
6. make sure the gaps don't line up on the "washers on the bolt"
7. make sure the bolt moves freely (and properly) in the bolt carrier
8. make sure that the bolt can move the buffer back far enough to cycle a round. if not, look for obstructions in the buffer tube (friend has a MagPul stock with a scew that protrudes too far into the buffer tube sleeve; it doesn't allow the buffer to retract adequately)
9. with the rifle assembled, cycle the bolt manually about 300 times. listen/feel for anything that would indicate the bolt carrier is not moving freely

i'll add more later if i think of anything...

[Suburban]

Bolt carrier rubbing on the magazine?

Does the problem only happen with aluminum or steel mags loaded to 28, 29, 30 rounds?

[Asmodeus6]

I had a similar problem on my first trip out with my first AR15. The gas block on mine was not tight and it caused it to short stroke after a few shots.

[soberbyker]

First trip out with my home grown AR (Stag receiver, Del-Ton Complete upper kit) had a similar problem. Turned out the be the gas tube not lining up properly on the barrel, off by a ridiculously small amount but enough to not strip the next round most of the time. A small adjustment later and it's worked fine ever since, even with the cheap ammo.

.

[Legion_Prime]

Short stroking does seem to be the most likely culprit as stated before. The easiest way to check for this is to place a known good magazine with 1 round in and fire it. If the bolt does not lock back you are short stroking.

Is it doing this on any one particular round? (first in the magazine, last in the magazine)
Are you holding the magazine while firing or resting/pushing it on anything while firing?
Is it doing this on any one particular magazine or type of magazine?
What springs/followers are in your magazines?
Whose upper is it?
Whose barrel is in it and has any machining work been done to it?
Has the gas block, tube, key or barrel ever been removed?
Whose bolt is in it?
Have the gas key screws been properly staked
Who assembled your upper? (you, factory, bubba down the road a piece)
What type of ammunition are you using?

The most common culprits in short stroking tend to be low powered ammunition and improperly installed gas keys. There are far more possible reasons though, with a bit more information we can be of more help in nailing down possible causes.