New rifle eject issues

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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New rifle eject issues

Postby Jhump » Sat Dec 02, 2017 1:05 pm

All, I have searched on the site for my answer and don't see it...could have missed it.
I have a brand new 16 upper and am shooting hornady black ammo. Have 2 converted mags and one factory 5 rd. The rifle will only fire 1 rd and not get it ejected but it is chambering the second..do you guys think I need to polish the ejector. Thanks for any help. Josh
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Re: New rifle eject issues

Postby Al in Mi » Sun Dec 03, 2017 9:43 am

welcome.

what does it do hand cycling rounds? one thing to look at is the extractor, see if it has any burrs on it.

I've always broke in new uppers wet, meaning liberally oiled to the point of dripping, doesn't matter the caliber, just something I and other do.
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Re: New rifle eject issues

Postby Bmt85 » Sun Dec 03, 2017 10:51 am

I agree with Al.
Check the extractor. Look for burrs, but also check to make sure the corners aren't biting into the rim. Had one build that was giving me issues like a fail to eject, it was actually the extractor holding onto the rim. Simple fix is to remove the extractor, and lightly file (round out) the corners. Also run a new build wet, as Al stated.
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Re: New rifle eject issues

Postby Deereman2 » Sun Dec 03, 2017 9:50 pm

Change ammo,I went to Remington 260 grain.fixed my problems
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Re: New rifle eject issues

Postby Al in Mi » Mon Dec 04, 2017 6:39 am

Deereman2 wrote:Change ammo,I went to Remington 260 grain.fixed my problems


just my .02 cents, but there is another problem if just swapping ammo fixed it.

welcome aboard :)
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Re: New rifle eject issues

Postby Rklenke » Sat Dec 30, 2017 11:05 pm

Figure any fix out yet? Mine recently started doing this with handloads and I didn't want to start another thread on the same thing. The rifle will fire, bolt will travel to the rear without ejecting, so I know it's getting gas. I have to manually extract each brass case by pulling the charging handle. Some take quite a bit of force to extract.

When I first started shooting this upper, it was flawless, then it FTE every few rounds, now it's every shot.

I'll have to shoot some Hornady Black tomorrow to see if it's my handloads, which are within Hornadys 10th manual specs.
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Re: New rifle eject issues

Postby Al in Mi » Sun Dec 31, 2017 6:46 am

Rklenke wrote:Figure any fix out yet? Mine recently started doing this with handloads and I didn't want to start another thread on the same thing. The rifle will fire, bolt will travel to the rear without ejecting, so I know it's getting gas. I have to manually extract each brass case by pulling the charging handle. Some take quite a bit of force to extract.

When I first started shooting this upper, it was flawless, then it FTE every few rounds, now it's every shot.

I'll have to shoot some Hornady Black tomorrow to see if it's my handloads, which are within Hornadys 10th manual specs.


Give it and the bolt a good cleaning and lubing, checked the gas block to see if it's still tight, did you try a different mag by chance?

What handloads are giving you the problems?

also be interested to see if the factory ammo cures it.
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Re: New rifle eject issues

Postby Rklenke » Sun Dec 31, 2017 7:39 am

Everything was clean, but I'll double check around the extractor area. I actually wasn't using a magazine, just hand feeding one by one. When I do use a magazine, the bolt will cycle and lock to the rear. Using 300 grain XTP over 32.2 LilGun.
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Re: New rifle eject issues

Postby Rklenke » Mon Jan 01, 2018 10:34 am

After cleaning and lubing my first shot cycled fine. The next shot stuck the brass in the chamber where I wasn't able to extract with the charging handle. I had to drop a cleaning rod down the barrel. Since I'm firing brand new starline brass, should I run a film of dry lube on all my cases?

I wasn't able to shoot any factory ammo since I had that case stick and didn't have the cleaning rod on me.
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Re: New rifle eject issues

Postby Hoot » Mon Jan 01, 2018 12:12 pm

Rklenke wrote:After cleaning and lubing my first shot cycled fine. The next shot stuck the brass in the chamber where I wasn't able to extract with the charging handle. I had to drop a cleaning rod down the barrel. Since I'm firing brand new starline brass, should I run a film of dry lube on all my cases?

I wasn't able to shoot any factory ammo since I had that case stick and didn't have the cleaning rod on me.


Never Lube Cases Before Shooting! Not even dry lube.

During ignition, the cases expand against the walls of the chamber and need to cling to it until the bullet breaks the seal as it exits the muzzle, lowering that pressure. If the cases don't cling, a lot more force will be exerted upon the bolt than it was designed for. Lubricants, even a small amount, can cook off from the case heating up during ignition while being squeezed between the chamber wall and the outside of the case. The molecular components in the lube can "crack" down into adhesive solids under those extreme conditions. Ever see the plastic-like residue in a popcorn popper after many uses without cleaning them. That plastic like compound is the result of the oil "cracking" down. The buildup of those deposits, while very thin, on the chamber walls, makes it sticky and more prone to additional buildup. Its a good reason to clean the barrel at the range when you're done and it's still warm. I'm talking proven track record solvent (Read: Not CLP oil) bronze brush and tight patch repeated passes. You'll feel it when you've done enough passes. Its also why you push several dry patches through the chamber and bore, Before shooting the rifle. Never shoot out the protective oil left in it from the last cleaning session.

Ar a COL of 2.26, 32.2gr of Lil Gun is only a 65% case fill charge. You would be much better served using a more voluminous, slower burning powder with 300gr bullets, like H4198, H4227, even AA1680. A fast burning undercharged round can develop higher pressure, more than a stout load sometimes. This has been discussed a lot recently but bullets designed for 45 ACP use (Read: Non XTP Mag) may deform when they squeeze down to the bore dimensions as they move forward, forming a plug until the pressure increases enough to push them into compliance. That pressure spike which I might add is worse with faster burning powders, can result in the cases seizing up during extraction, even from an immaculate chamber. Under excessively high pressure, the brass is physically altered to where it doesn't shrink back enough after the pressure drops, to allow easy extraction, or doesn't shrink back at all.

There's a lot to understand about internal ballistics but fortunately there's lots information on the web at your disposal, to help get a mind's eye about what is happening in those first couple of milliseconds. Google, combined with good search terms, can do wonders. So can books.

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