Home Forums Hunting & Shooting AR and Tactical Rifles Failure to eject issues

This.

0.125 sounds about right if you intend to install an adjustable port.

You're getting advice to solve two completely different issues. Overgassing and undergassing can sometimes manifest as the same problem if you don't know exactly what you're looking at. And some of the verbiage used by everyone isn't quite the same.

Can you take a pic of the malfunction, or better a video?

What are the new gas block and gas tube supposed to accomplish?

The new gas tube and block are to get it back up and operational at this point. With the screw being stripped out on the block, I had to drill the stripped screw out to get it off. Once I got enough material remove I was able to "screw" the gas block off, which in turn broke the gas tube. I probably should have just left well enough alone and let it be. After I put the new extractor spring in after the first outing and played with the magazine a little, it fed steel cased ammo with no issues. It's just brass cased ammo it doesn't like.

What mags are you running?

Does the bolt reliably lock open after the last shot of a magazine(when the rifle is operating correctly with steel case)?

Yes, it does. I have not had a problem at all with that aspect when suing steel cased ammo, 50/50 chance it will do it with brass cased ammo. Load 2 or more brass cased rounds, forget it.

ASC mags, I don't think they are the issue, as they have been ran in my son's 7.5" 7.62x39 AR pistol and no issues at all.

Honestly, I think it maybe the darn feed ramps. My son is piecing together a new upper in 7.62x39 with a 16" barrel. He bought a Diamondback barrel, and the feed ramps are like glass compared to the one on mine.

Your son running brass ammo through that pistol as well?

I would try one of these

https://gunmagwarehouse.com/asc-7-62x39-ar-15-30-round-stainless-steel-magazine.html

Holy crap NO! That is absolutely terrible advice. Please don't lead new AR shooters wrong with this kind of garbage.

When you don't know what you're talking about, don't try to "help"; it only confuses the issue and makes everything worse.

There are a lot of guys throwing out ideas. Even the op has some funny thoughts. Now he thinks the feed ramp is the culprit because it isnt nicely polished? How TF does that have anything to do with failure to eject?

and you offered a ton advice to help out the op didn’t you.. I will take advice from Deflave about AR’s before I took any advice from you.

It’s either gas issue or the mags he’s using. The op said it shoots fine with one round, ejects, bolt locks back. But when he puts more than 2 rds in the magazine it’s starts having issues. So I would try a different mag.

He’s running both steel and brass ammo.

While we’re throwing out theories, the dimensions of the loaded rounds may be an issue. If the brass ammo sits slightly higher in the magazine, it may impose drag on the bolt carrier, slowing it just enough to cause problems. This would account for the difference between one round and two in the mag, and the friction difference between steel and brass. Recommend you measure the difference between the two and see if it’s even a factor.

Old70

Lots of pitballing, but here goes another.

old70 has me thinking.

Ever try loading a few steelcases, the a brass?
It would be interesting to see if that made a difference.

The brass case is softer than the steel case. The brass case expands/seals tighter than a steel case.

Upon firing, the pressure/heat expands the brass case tighter against the chamber forming a great seal. Steel case essentially does the same, but not to the same degree.

As pressure/temp drops, the seal breaks, facilitating extraction.

If the bolt is trying to unlock/extract before the brass case has 'broken seal' the extractor hook can jump the rim, leaving the fired case in or partially in the chamber.

The bolt continues rearward, picks up the next round from the magazine, and pushes it forward toward the chamber, except the chamber is not empty.

Classic double-feed type of jam.

An adjustable gas block is one way of addressing the situation, by dialing down the volume of gas.. A heavy buffer will usually work too, as it retards unlocking/extraction.

I've been through this with one of my 5.56. An H3 buffer sorted it out nicely. Now I'm running (yes I said 'running'...lol) H3 buffers in all my carbine lowers, and everything runs well. I'd probably need the standard buffer in the arctic.

I'm no expert, but I believe that this is what's happening. Especially since the OP indicates that lockback is happening with a single round.

Hudge said, "I think the problem is a rough chamber or feed ramps at least is the issue issue. I went out again today with a clean chamber, and a heavier buffer. First mag I ran through it was all brass, damn thing was a single shot. One shot and failure to eject, clear it and fire again, same thing. I put in a new mag with all steel casing, not one hiccup. I looked at the brass from the ones I had issues with, and there are rough spots on it. I got home and broke the AR down, and put my pinky on the feed rails, darn near cut my finger it was so rough. I guess I'll brake out the Dremel and give it a nice polish. The only problem, I won't be able to hit the range again for several weeks."