AR cycling question. any thoughts?

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Freddymac

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I bought a bushmaster XM15 (20 inch bbl, standard stock) a couple of months ago and I’m experiencing a funny cycling issue. It only has about 500 rounds though it, but it seems to cycle very slowly. I’m used to shooting my CAR15, and it seems like I don’t even notice that it is cycling except for the casing flying through the air. I called bushmaster, and they said that they have never heard of this before. Has anyone else ever noticed this? Anyone have any thoughts on why this might be happening? Could it be a figment of my imagination?

Any help would be greatly appreciated.

Thanks,
-Fred
 
Are you having any reliability problems? What about it seems slow--that you can't pull the trigger faster than it cycles, or you're hearing the spring?

If you have access to another buffer and spring, try changing those and see if it makes a difference.

You can also try the AR15 club on Glocktalk or AR15.com for further advice.

hth
 
Slow cycling AR:

Most new AR's I've delt with had a certain amount of break-in time neccessary before they became smooth shooters. I've usually just used a good amount of teflon based lubricant (take your choice) or LSA and fired some rounds through it. After a while the action smoothed out.

I'm not saying this is your problem -- just this is what mine was and how I addressed it. If you go this route make sure you clean the rifle well and wear shooting glasses. The lube will fly and get in your eye - no fun!

Note: There are some people out there who will say the AR doesn't need lubricant -- I think they are wrong in all but the most dusty climates. The AR does need LSA and more cleaning care than say an M1 or FAL (smaller tolerances due to the round I think.)
 
It seems to me that the speed of the cycling is controlled by the amount of gas pressure being vented through the gas tube back to the bolt carrier. Perhaps your're shooting ammo with a few weak rounds mixed in that deliver lower pressure?
 
Make sure the piston rings on the back of the bolt are staggered - no two gaps are lined up. Also look to see if bolt carrier key mates up with gas tube. Sometimes they are pushed over to the side and the gas does not get into the bolt carrier well enough to make it cycle. HTH
 
cuervo

yes- on both accounts, I can pull the trigger faster than it can cycle. And I am hearing the spring (it kinda sounds like a garage door spring... like a squeeky twanggg). All ammo usd in it so far was S&B or black hills, so i don't think that the ammo is the cause, and I have had no failures or malfunctions. I checked the gas rings, and they are staggered- no overlapping spaces.
 
Since we're on the subject, I have the exact same Bushmaster rifle. I fired it the other day and it performed fine during the first mag. I loaded 15 rounds into my next mag and began to fire. After each shot, the bolt does not open all the way up to eject the casing and I had to manually pull the charging handle to cycle the spent casing. The bolt was opening barely a 1/2 inch. After about 5 rounds, it got to the point where I had to exert some strong force to pull the charging handle back to eject the casing, almost couldn't do it. I disassembled it and could find nothing out of place or broken. Could something in the reciever warp from shoddy manufacturing? Suggestions are much appreciated.
 
i think i have a theory. it's hard to tell without actually seeing your rifle but my guess is that after becoming accustomed to the short gas system with its much more violent cycling on your CAR that perhaps the rifle length gas system only seems to be cycling too slowly. if this is not the case and there is a genuine problem then a break in period can help, as another poster mentioned. if the problem doesn't go away, you'll probably have to send it back to bushmaster. it could be any number of things but a poorly drilled gas port could be one and bushmaster did have a brief run of rifles with improperly staked gas keys. if your rifle is a few years old (still possible, even if you purchased it new), then the latter may be the case.
 
I hear that same sound from the buffer spring all the time with my issued M16A2, yet I've never had any malfuntions or jams, this is with firing all military ammo, the 62 grain stuff. I never lube the buffer assembly, never felt the need, just makes two more parts you have to clean when it comes time to turn the weapon in. a quick wipe down is all its ever needed.

Funny thing is when I'm qualing, and I'm really in the zone, it seems like the rifle takes for ever to cycle the action, yet when I'm just burning up rounds, either in semi or in burst it seems to function at the normal rate. just a matter of perception I guess.

you could try this, put the buttstock of the weapon against a supported hard surface and fire the gun, if its still cycling slow then you have just ruled out the human error part, and then you can look at the gas tube and bolt carrier for signs of trouble.
 
Freddy, a litte grease on the recoil spring will quiet it down some. I once complained of this to someone that likes ARs, and his reply was that the sproing is on purpose so that you can tell the rifle is working as it's supposed to. Once I got used to it, no big deal, but the grease did help some.

If it is cycling okay, I would think the gas system is okay. It is the buffer and spring that control the cycle rate. You can look to see if the gas system is leaking at the front sight, so maybe all the gas isn't getting back to the chamber, but I think that would still show itself with short-cycling or something similar, not just slow cycling.

Exar, the first question I'd ask is what happened when you switched back to the original magazine, if you had the chance to. This could have just been a magazine not fitting right and rubbing the carrier. Was the a GI magazine or aftermarket blue steel?
 
I was only using one mag and reloading it when the issue occured. It was a GI. I also tried swapping mags and the problem persisted. Both mags are GI.
 
Exar -- what kind of ammo were you using? If you've been using Wolf, you may have a buildup of the lacquer or poly coating in the chamber.
 
Exar - lube the bolt (not the carrier - the bolt inside the carrier) liberally with CLP and report back. Betcha a Coke that the problems go away.....
 
Question

What exactly do y'all call a "GI Magazine"? Does it mean anything specifically for AR's?

Maybe it is with other guns as well, but I have seen/used some pretty crappy mags that all claimed to be "GI".
 
Is the carrier key staked down? Bushmaster is notorius for shipping weapons with carrier keys that are poorly staked or completely unstaked. Loss of gas pressure there will cause the action to slow and eventually you will experience a short recoil malfunction. Never depend on locktite to secure the screws that hold the carrier key to the bolt carrier. They must be tightened down all the way and then staked in place.

HTH
Jeff
 
GI is any of the contract magazines, which can be found at Fulton Armory. They are all aluminum.
http://www.fulton-armory.com/ARMags.htm

The most notorious non-GI magazines are blue steel and can have very bad feeding problems. This is not to say that all of the contract magazines were perfect, which they are not as the FAQ above talks about.
 
Hmmm. I just recently bought the same rifle. Before firing it, I broke it down, gave everything a generous application of CLP, then wiped the parts dry. I've put around 300 rds of mixed ammo through it- Federal, UMC, Black Hills, and Ultramax without a malfunction or a cleaning yet.

I’m used to shooting my CAR15, and it seems like I don’t even notice that it is cycling except for the casing flying through the air.
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All ammo usd in it so far was S&B or black hills, so i don't think that the ammo is the cause, and I have had no failures or malfunctions.
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I see where you are going- you are worried that there isn't enough 'oomph' behind the cycling?? Mine seems to shoot soft as well, but then again I'm more used to shooting an M1. ;)
 
I'm using .223 British surplus.
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If it is Radway Green I feel your pain.

That is the only ammo my RRA mid length has problems with.

Failure to extract issues as the gun heats up. The extractor will actually will rip a chunk of the rim off the case trying to get it out of the chamber.

My gun has fired over a thousand rounds of M855PD with no failures, over a thousand rounds of M193 with no failures, over a thousand rounds of Winchester White box value pack ammo, the gun loves it.

The Radway Green SS109 just will not work :banghead:

It is either a combination of brittle brass and a tight chamber or maybe a powder that is too fast and the gun is trying to extract while chamber pressures are too high.

I have two whole cans (1800rnds) of the stuff and can't shoot it.
 
Try some 5.56 milsurp ammo.

I think it is loaded hotter than .223.

The sproing sound is normal.

The other guys are right, gas key, lubed up, possible gas leak around front sight gas block. All things to look into. You should be able to rip off bursts pretty fast without outrunning the gun with your trigger finger.

Carbines do cycle faster than rifles keep in mind.
 
It does seem weird that it is slow enough that you can pull the trigger before it puts another round in the chamber; but it is still able to cycle the round into the chamber. Usually if it was that slow, it wouldn't be able to feed the next round.
 
British Radway Ammo

Not to hijack this discussion -- but I'm glad someone said something about Radway Green ammo. I was just about to buy some but don't think I'll waste my money on it now.
 
Not to hijack this discussion -- but I'm glad someone said something about British Radway ammo. I was just about to buy some but don't think I'll waste my money on it.
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If you get a chance to try it out first take the oportunity. Most people who have bought it have been happy with it and its function. My buddies Bushmaster MForgery had zero issues with ammo out of the same can.

It is surplus NATO ammo. Why it will not work in my gun is a mystery. Probably a slightly tight chamber.

I got a good price on it also, nice bandoliers all loaded in a ammo can.

80% of those that rated it at ARFCOM had zero issues using it.

M193 is around 100% satisfaction.
 
I had a slow mo full length Colt with an Ace SOCOM carbine length stock and DPMS carbine buffer and spring. It was real slow chambering rounds(you could watch it kinda push them in) and would hang up when fired until hot. A Wolffe extra power buffer spring and a D ring on extractor(just in case!) fixed it up! I shot 1000 rnds of Radway green in a 5 day course last month!
 
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