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View Full Version : AR problems, want to borrow it and see what you think it is? (south bay)


mk3mitch
11-07-2009, 1:45 PM
Hey guys, So I am on my first OLL, a Stag upper and an S.I Defence lower. The thing shoots straight and looks cool, but it keeps jamming!!! It always fails to feed every few shots. I have tried FOUR different mags of four types. A 10/20 10/30 and two separate regular tens and it keeps doing it. I went minimal lube to a TON, also tried three types of ammo. It seems like it just doesnt want to pick up the round out of the mag, sometimes it puts a big scratch on the upcoming shell, sometimes when I fire the last shot and its empty, the bolt closes! It's supposed to stay open! Anyway, are you near me? I am in Hollister, If you seem legit, you can borrow, and shoot as many rounds as you want from it if you can figure what the problem is! Let me know if your interested.

supermario
11-07-2009, 1:54 PM
It seems its not the mags or ammo and its lubed and cleaned (correct?). If you dont wanna spend alot of $, try a few cheap items to replace. Like the buffer spring and buffer, maybe the spring is too weak to strip the round off the mag. I dont know much but thats what i would try after trying the mags. There are alot of guys on that know AR's like the back of their hand. Hopefully they will chime in. Try to figure it out yourself first. Thats what i do, makes me feel better that i can repair my own weapons. Especially an AR. Go through the process of elimination. Of course you need $ to replace parts, but then again, you can save those parts bought for a future build.

mk3mitch
11-07-2009, 1:56 PM
I don't believe it to be the spring, as it tends to ride the bolt over the rounds, not get stuck engaging them.

J_Rock
11-07-2009, 1:58 PM
Hey guys, So I am on my first OLL, a Stag upper and an S.I Defence lower. The thing shoots straight and looks cool, but it keeps jamming!!! It always fails to feed every few shots. I have tried FOUR different mags of four types. A 10/20 10/30 and two separate regular tens and it keeps doing it. I went minimal lube to a TON, also tried three types of ammo. It seems like it just doesnt want to pick up the round out of the mag, sometimes it puts a big scratch on the upcoming shell, sometimes when I fire the last shot and its empty, the bolt closes! It's supposed to stay open! Anyway, are you near me? I am in Hollister, If you seem legit, you can borrow, and shoot as many rounds as you want from it if you can figure what the problem is! Let me know if your interested.

Sounds like classic short stroking. You got a lemon upper(stag lol) either a problem with the gas block or the BCG leaking gas somewhere. Id have a word with the mfg.

Bud Fox
11-07-2009, 2:05 PM
Sounds like classic short stroking. You got a lemon upper(stag lol) either a problem with the gas block or the BCG leaking gas somewhere. Id have a word with the mfg.

Agreed. It seems like as the OP you've done all the correct and logical things. Call Stag, I hear their customer service is very good. Ultimately I think you'll probably just have to send the upper to get looked at. It could be as simple as a bur (sp.) from machining that's blocking 100% gas flow.

Good luck and don't stress, stuff like this is pretty simple and just something that was missed during assembly.

Trendkill
11-07-2009, 2:11 PM
Sounds like classic short stroking. You got a lemon upper(stag lol) either a problem with the gas block or the BCG leaking gas somewhere. Id have a word with the mfg.

Yup.... prolly short-stroking. Its not flying all the way back to grab a fresh round. And after the last round fired...it still isnt flying back far enough for the mag to engage the bolt catch.

Are you using steel case ammo...????

mk3mitch
11-07-2009, 3:07 PM
wow guys that sounds correct! Makes perfect sense! I will have to call up Stag and see what they say.

Josh3239
11-07-2009, 4:40 PM
Shoot it more. If it is short stroking, which it sounds like then likely the gas port was drilled slightly undersized and as you shoot it more the gas port will open up slightly more and more and the burrs will go away. I had to break in my AR this way as well.

Although it is likely the gas port, check the "lock up" between your carrier key and your gas tube. Make sure the carrier key isn't loose, I doubt Stag staked those screws, I'd make sure they were staked.

Buddhabelly
11-07-2009, 4:46 PM
Go to the range with another guy with a known-working AR.

Put your upper on his lower. Let him shoot it.
His upper on your lower. You shoot this.

If he has problems, your upper is bad.
You have problems, it's your lower.

Then continue to troubleshoot the problematic upper or lower to smaller and smaller subassemblies by swapping to know-good parts.

Good luck.

Trendkill
11-07-2009, 5:35 PM
Go to the range with another guy with a known-working AR.

Put your upper on his lower. Let him shoot it.
His upper on your lower. You shoot this.

If he has problems, your upper is bad.
You have problems, it's your lower.

Then continue to troubleshoot the problematic upper or lower to smaller and smaller subassemblies by swapping to know-good parts.

Good luck.


Right.....and when doing so...make sure to permanently swap over all the other guys really good stuff with your stuff and swear to him that it was like that in the beginning.

Problem solved... ;)

Good idea Buddah