ar jamming

[glock27owner]

i recently finished building my ar15 .i have shot it several times now and with 3 diff mags . it appears to be jamming sometimes when the bolt is moving forward .it will sometimes not even load the next round. sometimes starts pushing the round forward but then stops . i think it may be the mags holding too tightly on the bullets??not sure it is oiled and clean.help.

[Whiskey Delta]

i recently finished building my ar15 .i have shot it several times now and with 3 diff mags . it appears to be jamming sometimes when the bolt is moving forward .it will sometimes not even load the next round. sometimes starts pushing the round forward but then stops . i think it may be the mags holding too tightly on the bullets??not sure it is oiled and clean.help.

I am by no means an expert, but I would ask you what you built the AR out of? An 80 percent reciever that you yourself finished? A reciever that was made by a manufacturer? Who built it? What parts kit did you use?

Are all nuts tightened down? Barrel nut? Any binding when you cycle the action with nothing in the mag well?

Have you used different ammo?

What kind of buffer recoil spring do you have? That would be the second area I would look at.


Third, you say you used three different mags. Are the different brand magazines? Try and get magazines that are milspec at the minimum. Orlites and other such esoteric type might have problems.

Keep us posted.

[glock27owner]

I am by no means an expert, but I would ask you what you built the AR out of? An 80 percent reciever that you yourself finished? A reciever that was made by a manufacturer? Who built it? What parts kit did you use?

Are all nuts tightened down? Barrel nut? Any binding when you cycle the action with nothing in the mag well?

Have you used different ammo?

What kind of buffer recoil spring do you have? That would be the second area I would look at.


Third, you say you used three different mags. Are the different brand magazines? Try and get magazines that are milspec at the minimum. Orlites and other such esoteric type might have problems.

Keep us posted.

its an armalite upper and lower reciever kit bolt was assembled i put the rest together . barrel is tight . 3 mags 2 brands 1 came with the kit . adj stock . forget the brand a cheap one came with stock tube and spring.tried diff ammo also with mixed results no real definate pattern exactly.i wonder if i just file down the curls on the mags where it holds the bullet a tiny bit if it would help. cause it seems like it holds the bullet very tightly mabye needs to break in.

[synergy]

can you get us a picture?

[glock27owner]

can you get us a picture?

A picture of the jam?...next time I go to the range I will bring my camera

[synergy]

A picture of the jam?...next time I go to the range I will bring my camera

Yeah, if we can see where the round stops in the feeding cycle, and what is touching what...it makes diagnosing the problem a lot easier.

[mgs]

If the rifle feeds ok from a locked back bolt, the recoil spring is fine (feeding 1st round from mag). If the rifle is short stroking, low powered ammo or a leaking gas block could be the problem. The AR runs best wet so make sure the bolt carrier is lubed well. Also make sure the gas tube is aligned properly to the bolt carrier and not binding, Mike.

[ungawa]

I was waiting for the more knowledgable people to chime in and mgs (Mike) covered it.

With the firearm on safe and point downrange lock the bolt open. Insert mag and drop the bolt. If it feeds every time this way, but won't feed after firing, then you are probably short-stroking. Weak ammo or gas system problems are likely. Another test would be loading one round in a mag and firing it to see if the bolt locks open properly. But I think in your case trying to chamber from a locked open bolt might provide the useful info.

If weak ammo or gas system are not the issue it could be bad mags, something could be wrong with the recoil buffer spring, it could have been put together wrong, there could be bad parts, or the bolt could be hitting the bolt hold open button.

There is one more thing, although it seems unlikely. And I probably should have put this in the "AR or AK" thread. When I got a used AR it was very clean. I went out and fired 200 rounds through it and did not clean it. Two days later I went to load it and the bolt would not strip a round. This was pretty alarming. I took it apart and cleaned it but it did not seem dirty. I think it may have been the type of lube the guy before me put on it gummed up. I've been hearing about this sort of thing with a variety of firearms if they were lubed and then not shot for a while. It is possible that a good cleaning with a good solvent and proper lube may solve the problem.

[mgs]

Good follow up ungawa! Firing one round at a time from a locked open bolt to a locked open bolt say's everything is working fine including the magazine.....Mike.

[Steelblitz]

Make sure the bcg is well lubed for starters.

If you pieced this build together, make sure you have the correct buffer spring and buffer. Too long of a spring or too heavy of a buffer could cause a short stroke. A short stroke in this case may be more noticable with cheaper ammo like Wolf which can be underpowered.

Last, you might have a gas leak or the gas port may be undersized. It's happened with armalites before.

List the mags you tried, the ammo, the exact parts used in the build, tell us if everything is new/used, etc....