My AR-15 Is Leaking Gas... Is that Normal?

T

taco

New member
Okay all you AR fans I got a question for you.

Last night for the firest time I took the forearm off my new Bushmaster and noticed that there seems to be gas leak just at the point where the gas tube goes into the gas block (front sight assembly). On the first one or two inches of the gas tube and the barrel behind the gas block there was something that looked like dry soot which I assume is gas from firing. There is not a lot but is very noticable and the heat shield on the top forearm has some too. Is this normal on AR rifles? If the gas is leaking does that mean my rifle will not be reliable since it will not be able to push the bolt back with full force?

This rifle has been fired just over 600 rounds since I got it last month and I have had some "double feeds" and failure to chamber a cartridge. Could these problems be related to leaking gas?
 
Yes, it is normal for there to be some leakage
where the gas tube enters the front sight base.
As long as your rifle is operating fine it is OK.
 
I had the same problem with my Jeep. It also leaked gas. A new gas cap cured the problem.
SORRY!!!!!, I just couldn't resist. Enjoy your AR
Best wishes to all - John K
 
Most of the malfunctions an my AR are magazine related.
Mark your mags and see if it only happens with a certain one.

As far as gas leakage; [insert smartass comment here]

good luck
 
Thanks guys.
I thought I had a problem.

Racegunner:
I started marking my magazines from the start. I have had problems with 3 mags while other 5 were perfect. Actually I think I had problems because I was not leaning into the stock. I was shooting off a bench so I just let the stock lay on the sandbag without touching my shoulder so the rifle just rocked back from recoil and did not have enough resistance to feed and eject properly. I'll try again next week to see if that was the problem.
 
"limp shouldering" a gun might cause your malfunctions. Should never do this. A weak spring could also be the cause. The gas leakage is normal.
 
Badger Arms:

Thanks for your post.

I'm suspecting "limp shouldering" as the cause of my problems because I noticed from my notes that 4 of the 6 problems occured with Winchester 45gr JHP load. Compared to other 55gr FMJ ammo from UMC, Winchester, Federal, IMI, S&B (steel case) and Norinco I shot on the same day the recoil from 45gr JHP was quite less (down loaded?). Combine low recoil and limp shouldering and I have failure to feed and/or failure to eject problem. I think.

Norinco and S&B had the most recoil and those did not have any problem.

Finally, do you mean weak magazine spring or recoil spring? I just assumed magazine spring.
 
With due respect to Badger Arms, I believe that you will find that gas-operated systems don't require resistance as do recoil-operated systems. You can fire your AR with one hand, and it'll function just as well as if you lock it in a vise.

I rarely use shoulder contact when firing my Bushy Shorty from the bench. I've never had a failure to feed or fire, in thousands of rounds of my reloads.
 
Thank you Walter, I was about to make the same comment. The gas entering the tube is at the same pressure, whether or not you are providing resistance.
 
Oh, by the way, is this a shorty model?
I've heard that some shorties (the 11" plus 5" flash suppressor) have trouble especially with low pressure rounds.
Also, I wouldn't discount the leak 100%...no one that has said not to worry has actually SEEN to what extent yours is leaking. Make sense?
Like the post that mentions "it is normal for there to be some leakage..." but how much is some?
And check and clean out the gas tube, it could be cruded up a bit.
 
Walter:

That wasn't the dynamic I was speaking of. Instead of loading the spring, the recoiling bolt carrier will push the rifle backwards with some of its energy. Therefore, a lightweight gun like the AR-15 will move backwards and the bolt carrier may not travel fully to the rear. Especially with 45 grain loads that might not drive the carrier with as much force.
 
I don't think the leak is normal.

I haven't seen them leak in a gov't M16 or a civilian Colt AR15. Of course, a tiny bit may not be a problem, but it's a matter of degree.
 
The gas leak is normal I wouldn't worry too much, but then again I shouldn't talk since my girlfriend always complains about my gas leakage (sorry I couldn't resist :D )
 
Recoil?

The AR15 IS an impulse-operated arm and free recoiling it CAN cause malfunction if the port pressure is low.

The carrier is projected back only a short distance by the action of the gas on the bolt/carrier assembly. It is possible a significant quantity of energy can be absorbed in free rifle velocity as to limit the carrier velocity and cause malfunction.
 
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