AR -15 ???

MIKE WISKEY

I have a ar-15 (sportsmans wharehaus)in the shop that 'short cycles', it's clean inside but it does have a colapsable butt stock. I test fired with radway green ss109 ammo same thing, feels like it isn't getting enopugh 'gas' or the spring is too strong. I checked the 'buffer', it has three steel weights inside. I removed them but no effect. any ideas before I tear into it??

dcs shooters

Check the length of the buffer. They may have put a solid stock one in, which is longer.

511pe

Hello, Don't tear into your gun just yet. Try 55g FMJ first to see if it cycles. Your gas tube should provide more than adequate impingement pressure to pop the bolt & carrier out of the locking lugs and feed the next round within the mag. If yours short strokes most likely your gas port may not be right. Either semi blocked, burred, or clogged up. AR15s have generous room for the gasses inside the gas block even if you don't space the block on a free-float hand guard from the barrel shoulder. Most likely that may be the issue or a semi clogged gas block or tube which is not normal for AR's or M16's. You could greatly benefit from a double tungsten buffer if you experience hang-ups on the feed ramps due to lack of inertia force to send the bolt carrier home. Also most AR15s have burrs on the feed ramps to resist the feed. Just knock 'em off with a stone or diamond file & blow out with an air gun. I feel your gas impingement system failed you so look there first.

MIKE WISKEY

thanks so far, the bolt cycles just far enough to cock the hammer but will not eject the empty.

midnightrunpaintballer

gas tube is plugged or has a leak. Same exact thing happened to my armalite and it was like that directly from the factory. I sent it back and they replaced it (no charge) and I have not been able to get it to malfunction in any way since! Take the bolt out and spray some WD40 or whatever you can get your hands on into the gas tube. If it runs out along the top of the barrel (or anywhere else except inside where it should be, then you have a leak. If it doesn't come out anywhere (even the inside of the barrel), then you have a blockage. I'd say you're much more likely to have a leak. Shooting hotter ammo MAY help cycle the action if there's a leak, but the problem won't just go away.

tsr1965

MW,

Make sure the gas tube is clean. Take the upper off the lower, and grab some break cleaner and spray it in the gas tube, with the muzzle pointed down. Also get some of those giant pipe cleaners we use for cleaning the gas tube. Repeat this untill the brake cleaner runs out the muzzle. If you have a stubborn pluged gas port, you might have to remove the gas block.

If it is not a gas problem, then there are two other things that could impinge the action. The buffer spring for a fixed butt stock was used in the collapsable one, and will not let the bolt travel back that far, and secondly, it could be blow by on the gas rings on the bolt, inside the bolt carrier.

These are just a tad easier to get apart than a 742 also.[:D][:D][:D]

Best

EDIT 1

MW,

quote:If it had the wrong buffer you (probably) wouldn't be able to chamber a round. the bolt and carrier look fine.

Not so fast. It can shorten the stroke enough that you may be able to do that manually, but upon actually firing the rifle, the bolt is already over the top of the magazine on the return trip, before the round comes up. But, it does sound like a gas problem.

richbug

Is the gas bock a pinned on one or a set screw one? I have had the set screw ones shift(even on high end guns like JP), which partially obstructs the gas port.

The cure is to put the block in the right place then drill a dimple into the barrel for the set screw to seat into.

MIKE WISKEY

THANKS GUYS, I'm inclined to look at the gas system next. If it had the wrong buffer you (probably) wouldn't be able to chamber a round. the bolt and carrier look fine.

garand101

Pull the bolt carrier group and make sure that the grooves in the 3 little rings are NOT lined up. Also make sure that your carrier key is tight and staked. And put the weights back in you buffer...Don't shoot it without the weights....they are there for a reason.

sandwarrior

I'm going with the blocked gas system problem. The Buffer has nothing to do with whether a round will chamber or not. It does have something to do with how well it feeds them though. Feeding comes down to gas and to buffer. If the buffer will go back, pick up the next cartridge and load it, then you have a gas problem.


Added:

Feeding is also dependant upon how well a case fits to have it chamber. This is most true with reloads. If they fit when you make them then it's back to gas/buffer.

v35

Installing new piston rings wouldn't be a waste of effort.
There's a one piece style that doesn't require spacing ring gaps 120 deg apart.