Ar 10 - 6.5 Creedmoor ejection issues

[CPA]

Hey guys, bought a Stag 10 upper, lower and BCG. Put a 20" match barrel and lantac gas tube/block.

I took it to the range for the first time yesterday and am having some ejection issues. The brass is either stove piping, or literally does a 180 inside the upper and gets slammed back into the chamber but head stamp first. Out of 30 rounds fired, literally 25 had jams. Brass was mangled every time.

The gas tube I believe is 0.936. Am I experience too much gas? not enough gas? BCG issues?

I know people say stove piping is a under gassed issue, although the full 180 I think is a over gassed issue no?

Any troubleshooting ideas before I send the rifle to stag?

 

[hlee]

Check the extractor. Sounds like it is not getting a good grip on the cartridge.

 

[2aBaC̶a̶]

+1 on checking extractor/ejector components.

Have you tried cycling some dummy rounds by hand?

 

[CPA]

That is a good point, I have not done that. I will grab a magazine and see if I can run it through manually.

 

[Spblademaker]

Too much gas. My 6.5 did the same thing prior to being adjusted. Although it only took 3 rounds to get the block adjusted. It’s not what would be caused by the standard stovepipe problem. Just that the brass is being so violently thrown around, sometimes that’s where the BCG is catching it.

 

[Yondering]

Too much gas. My 6.5 did the same thing prior to being adjusted. Although it only took 3 rounds to get the block adjusted. It’s not what would be caused by the standard stovepipe problem. Just that the brass is being so violently thrown around, sometimes that’s where the BCG is catching it.

This. Sounds to me like the rifle is severely overgassed. Gas tuning is pretty important on these large frames if you want it to be reliable.

 

[CPA]

So I got home and put some actual live ammo in the rifle. Magazine had 5 rounds. Everytime I pulled back on the changing handle the first run through it cycled the first four. Then on the last one it never a really released the 5th round. Just held it on a angle.

Then I did it a second time. And that copied the first test exactly.

Then a third time I really pulled the charging handle pretty rough and hard. Then released it quickly so it would slam. And then it cycled all 5 rounds including the last one.

Is it normal to have to really pull.it quickly and hard? Can you all cycle your rounds out by pulling slowly? I know my bolts I can go at a crawl and it will.still cycle no issue.

Or should I still pin this on gas?

 

[Yondering]

That's an ejector or extractor issue. Pull both out of the bolt and check for burrs, bad springs, etc.

 

[bfoosh006]

Also check the outside edges of your extractor claw.. they should be slightly rounded , rather then sharp.

 

[Ravenous]

This happened to me as well. Just like the other have said, check the extractor and ejector. If it were a gas problem there wouldn't be an issue when you manually cycle it.

 

[Landon4]

I had a 9mm ar which is blowback not gas but it would jam every 2-3 rounds, everything was new with a spikes 9mm lower Gibbs side charge upper and spikes bolt. I sprayed a lot of clp on the bolt and put 100rds through it flawlessly, it has worked fine ever since just acted like it needed some break in

 

[CPA]

I have added a couple of photos. So I took the pic before cleaning or anything on purpose in case it gives any clues to you guys. Those yellow lines that look like brass are just marks not actual brass.

Is the ejector supposed to be inward that much? I feel like the one side looks like it's much deeper into the bolt face circle then the other side?

 

[Yondering]

Is the ejector supposed to be inward that much? I feel like the one side looks like it's much deeper into the bolt face circle then the other side?

Sounds like you meant extractor, not ejector? Both look OK in the pics, but that doesn't mean they operate smoothly. The extractor could stand a bit of polishing on the forward face to avoid shaving brass when it's forced to jump over a case rim during the chambering process. Sometimes an overly stiff extractor spring will contribute to that as well.

 

[elmuzzlebreak]

So your biggest challenge with a 6.5CM AR10 is going to be the gas/buffer system tuning. Mine did a lot of the same and I ended up having to get a heavier spring to slow the whole system down. I'm not sure if the lantac gas block is adjustable but if it isn't I would recommend you get one because that will save you a lot of headache down the road. What ended up working for me was an Ar10 rifle buffer and a sprinco green spring. The other thing to consider is the sizing of the gas port. Some barrels are undersize, some are over size. There is no set "standard" in the AR10 world.

As to the slow manual cycling it depends on the gun. You can do it in some but in others you need to let that bolt fly.

 

[palmettoman]

I was having the same trouble you describe with FTE's until I upgraded my buffer spring to a Tubb's. One spring I used was too heavy, another too light causing false pressure signs, FTE's, torn up brass, etc. A Tubb's spring and gas block adjustment slowed things down a bit. Now it's much better.

 

[Randy_Lahey]

Yeah my PSA barrel/bcg needed a Superlative arms adjustable gas block. Had very similar ejection issues. I was able to get close to good with an Odinworks "tuneable gas block" but couldn't get it totally right. The SA gas block seems to have fixed it.

 

[bfoosh006]

I have added a couple of photos. So I took the pic before cleaning or anything on purpose in case it gives any clues to you guys. Those yellow lines that look like brass are just marks not actual brass.

Is the ejector supposed to be inward that much? I feel like the one side looks like it's much deeper into the bolt face circle then the other side?

Those ends on the extractor are awfully sharp... and don't look rounded at all.

If the edges of the extractor are too sharp... the case won't "roll" out... it will bind at those sharp ends.

And that could be enough of a "bind" ...

Check your brass rims.. see if they have any excessive marks on them.

 

[2aBaC̶a̶]

It should kick every round out the same once they clear the breech. Sounds like either your ejector sticking or your extractor not letting go.

Mess around with a case in the end of your bolt and feel for any sticking, it should kick the round to the side with a little spring force and the extractor should let go easily.