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

Everything I read says the empty case stays in the bolt, does not eject. And it only locks back 50/50

There is no way to diagnose this with the given info but everyone is throwing something out there.

Is your ejector and spring good? Doesn't matter what it does with steel, brass is the problem you're having. It could be a mag catch out of spec or weak ammo.

I must have misunderstood. I thought the spent case was staying in the chamber, or partially extracted but not ejected.

Some company and I don't know who they were/are was putting out some 450 Bushmasters that refused to extract and eject. My local gun guy did everything he could to get the problem guns (plural) to work. His last effort to get them to function was to open up the gas port. That fixed the problem. They were simply under gassed.

However, he used the number drills and picked out a number slightly bigger than the existing hole. If that did not work he went the next number up. He didn't just pick out a drill bit he thought was OK and use it. A 1/8th drill bit is .125" diameter hole. I think his final number was in the .090 range. .125 is probably going to over gas the rifle. Find someone with the numbered bits and work up from the existing hole until the gun is reliable.
kwg

If you have another (working) AR it should be simple to isolate the problem.

You are correct. My new gas block and tube will be here today, and I will get it back together and go one by one on the things mentioned to get it fixed.

"So it tries to put a new round in the chamber and the empty case stays in the bolt."
"One shot and failure to eject, clear it and fire again, same thing."

I just read what you wrote and tried to grasp how the empty case could stay in the bolt but it's what you wrote. In the future please note failures to eject are different than failures to extract.

I hope you get it sorted out.

Once you get the gas block off, stick the shanks of number drills in the gas port. Let us know what the size is of the largest drill bit that fits.

Based on what he's said, that steel case ammo functions but brass cased ammo does not, it doesn't really sound like a gas pressure / volume issue.

If there's enough gas to extract & eject the steel case, it would seem likely to be enough gas for the brass case ammo, absent some other contributing factor like the rough chamber...............maybe.

Really hard to get an answer from the crystal ball w/o see the gun.

If you ever get it figured out, report back with results.

MM

If the bolt won't let the brass case go, maybe check the ejector plunger/spring for crud.

also maybe compare rim diameter between the steel and brass cases. If the brass ammo has oversized rim diameter, that might be an issue depending on boltface diameter.

Yes, this. Small changes in gas port size, like going from .086" to .093", can have a big effect on how the rifle runs. One would have to be completely oblivious to this stuff to suggest drilling out to .125" without a lot more info and testing smaller port sizes first.

I go from .093" to .096" on a lot of my rifles and notice a large increase in reliability.

If that 1/4 bit don’t work move up to a 5/32 that should get that AR running for sure..

That would be a 3/32 correct?

.0937" = 3/32

MM

I use number drills. #40 is .0935" and #41 is .096"

20" barrels with rifle gas?

I thought that was settled long ago, haven't heard of any reliability problems with a 20" rifle.

Where did you get them from? Be handy to have a set. Thanks

The fact that you have to ask says a lot about whether you should be giving advice on opening up gas ports. Stick to what you know, instead of believing other blowhards and claiming it as fact.

Any good machine tool supply sells number drills, which you'd know if you had any experience with this sort of thing.

Yes.

Service Rifles are a different beast. They have really heavy barrels and parts, like gastubes, tend to get over-recycled.

IMO&E .093" 20" heavy barreled rifles don't have a particular affinity for powders like WC844, 845, SMP-842, 8208 and sometimes AR Comp & similar. A significant number of rifles simply won't run with those powders at that port size. If I were to speculate, I'd say it has to do with gas keys that were assembled without a sealant, but I'm not sure even that is necessarily 100%. .096" runs with any reasonable carrier and is what Frank White uses.

The heavier the barrel, the bigger the gas port needs to be.

I inherited the number drills, but I'll bet Harbor freight stocks them. You need to run them well lubed at high speed when using them to ream stainless.

Harbor freight sells them as well.