Help with an Ar

Adamg_55

CGN Regular
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Hey guys, i finally has the opportunity to take my second hand AR-15 and i had trouble with it. I went to the range today with my Colt AR-15 A2 Hbar. I bought this gun and it has sat for a while since i switched clubs, so today i finally got to shoot it. So the problem was it would fire and then extract the cartridge and not chamber the next one. It did work on and off, but the most amount of shots i could get was 3 before jamming. so i took a pic of what was happening.

It was cold today -8 while i was shooting and the gun was lubed with generic Remington gun oil. I used 2 types of ammo: The value packs of Winchester 223 Rem 45 gr. jhp high velocity 3600FPS.
The second brand of ammo was Remington UMC 55 gr.

The UMC seemed to not always jam on the first shot, but jam on the second or third.

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So the gun would fire extract the round every time and then jam when the bolt comes forward. If i pulled back on the charging handle a little and then let it go it would chamber and fire. I used 3 different magazines. I have no ideas what to do, so help is appreciated.

On a better note my m14 that i brought with it functioned flawlessly, i just didnt bring enough ammo, but brought more .223 instead
 
How long is the barrel of the rifle? Maybe its not getting enough gas?

Nope.It is stripping the round from the mag so it is not short stroking.

Lube it with something good like Slip 2000 and try other mags to see if the problem goes away.
 
soak up your bolt with some sort of gun oil, CLP,etc.

Keep it wet and report back. Looking at the pics it looks pretty dry.
 
Don't use lube on your guns below 0. Keep it dry or use graphite powder. The carrier might be seizing in the buffer tube on the forward action. Or, the chamber could be fouled as well. Excessive lube combined with carbon is an AR's worst enemy.
 
how much oil did you use? should be bone dry almost in this weather
also the return spring/buffer can be a suspect though if I remember right, use to have the same kind of problem in the moe when the gas key was gummed up, any bit of extra oil would act like a glue and slow down the action a bit, just eanough to cause a missfeed
 
I do believe it is a gas problem. I would replace the gas rings on your bolt and give it another try. You would be surprised how the action is affected when there is insufficient gas. The bolt is not being pushed far enough back which means there will be insufficient energy created by the buffer spring to push the bolt forward again with enough force to completely strip a round off of the magazine. Hence the need to pull back on the charging handle to complete the process.

Gas rings would be my first suspect. They are inexpensive and easy to replace so try that first. And always carry a spare set ...just in case.;)
 
Slow it down here guys, it is a 20" Colt ...the best of the breed in terms of reliability. The gun is of some age. Tear it down, clean and lube just to be safe. Get some good mags, P-mags would be nice. Bin the 45 grain for sure and the UMC is not great ammo either ( I had trouble with it as well)...get some Fed or Win 55 or 62 grain and I think your problems will go away. Given that age of the gun it wouldn't hurt to replace some of the small wear parts though I don't think that is your problem. As far as the gas rings go, go ahead and replace them but I have run my Colt with gas rings so worn they were half moons and super sharp...they gun still ran anyway.
 
Feeding problems are almost always mags. Take them apart, clean and lube the bodies, followers and springs. If it still doesn't work, change mags. By your own account, those functions that belong to the rifle are working fine.
 
Ok so it was most likely too much lube. Is it ok to not use lube on an ar -15? I'm gonna go out this weekend and give it another go. Should I not use lube? Or is there something better for below 0 shooting.

Where can I get graphite powder?
 
This is a feeding problem, what is it to do with gas ring?? The bolt is pushing the round into the chamber already and got stopped dead in the middle.

Looks like something is dragging on the bolt carrier too much. My supicion will be magazines - like s**tty aftermarket magazines made by USA mag or ProMag....gun show specials. The feed lip is too thick and make contact with the BCG.

-8 is not that cold at all.
 
I tried 3 different mags, one was the one that came with the gun, the other 2 are brand new 10 rounders from questar. I will be going to the range again this weekend so I will dissasemble relube and get some heavier grain bullets, and I will report back.
 
I tried 3 different mags, one was the one that came with the gun, the other 2 are brand new 10 rounders from questar. I will be going to the range again this weekend so I will dissasemble relube and get some heavier grain bullets, and I will report back.

I say again...get some good mags ...

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This is a feeding problem, what is it to do with gas ring?? The bolt is pushing the round into the chamber already and got stopped dead in the middle.

quite often that would be a result of "riding" the cocking handle, when you pull the cocking handle to the back, stop and then release the handle, especially if the mag spring is really tight (that usually happened when there was more then 30rds in the mag)
if there is anything to disturb the action (like a sticky bolt) it will lead to misfeed as seen on the pic
 
Hi:
You may need to check the gas tube if it's straight or bent, it shouldn't have carbon deposite in (bolt carrier) gas key hole which will cause lot of friction. Also check the movement of buffer and buffer spring, it should move forward freely. Cam pin and bolt should be able to move/twist freely too. Try to chamber and extract the rounds by hand and look into the ejecting port while the bolt carrier is moving forward stripping the round from the mag. I believe you could see the cause of problem. Just me .02 cent. Cheers.

Walt S.
Calgary, AB
 
I just had the same issue with my 16" Bushmaster. In my case the gas rings had lined up (somehow) and the lubrication was not what it should be (the rifle had been in the safe for about half a year). A quick disassembly/cleaning/lube and she fired right as rain again. I won't be neglecting her anymore.
 
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