Getting popped primers in new barrel

[glock40cal]

I recently switched barrrels on my Bushmaster from hbar to m4. Went to the range to sight in and got 4 popped primers out of 80 rounds. Any ideas what is going on? Thanks!

[ErikL]

Popped Primers are do to high pressure. Is the ammo you are shooting from a lot that you have previously fired and known to have no problems with? Are you shooting a Mil spec or surplus ammo? If so what kind? What chamber does the barrel have...Or what chamber does the barrel say it has? What is the temperature where you live? Has the ammo been sitting in the truck of your car or directly in the sun prior to shooting? There could be a lot of possible answers, I'm guessing mil spec or surplus ammo in a tight chamber, but it could also be do to lack of un crimped primer in a fairly hot loading or reloaded ammo.

[glock40cal]

The ammo is department ammo-federal american eagle 55gr 223 fmj. No known issues to this lot. temperature was around 90 degrees or a little higher on that day. chamber says 5.56 on barrel.

[markm]

To get popped primers on Federal AE, you need to have some big problems. That ammo isn't that hot.

I'd have your gun checked out. (headspace, chamber dimensions, etc.)

[ST911]

Is the new barrel a Bushmaster, or other? BM wouldn't be high on the list of usual suspects.

Agree with demigod... If AE is popping them, they have a bad lot, or you have a bad barrel. Deadline the gun and ammo pending further diagnosis.

Try the ammo in a known-good barrel, esp a Colt if you have one around.

[CarlosDJackal]

Contact the ATK group with the lot number and find out if they've had other instances. I still have 3 or 4 boxes of the Federal Gold Match 69-grain HPBT from about 5 or 6 years ago because I was experiencing the same issue shooting it out of my Bushmaster 24-inch Varminter.

The guys I talked to at Federal insisted that it was the rifle. Come to find out they had a bad batch of cases that was made from softer than normal brass. I kept telling this moron that I was not having the same issues with other ammo makers and even the same ammo from a different lot. But this dipshit would not even listen.

Years later I talked to an ATK rep and he verified that it was not the rifle. I told him that he can tell his bosses that my experience with the guy I talked to resulted in my changing ammo manufacturers (I switched to Black Hills for accuracy ammo and still avoid anything Federal for any of my guns).

You might want to try other ammo manufacturers just to verify it's not the ammo. Good luck!!

[sff70]

One possible cause of high pressure that manifests as popped primers is a chamber that is not spec.

If you can find someone with a set of gauges, have the chamber checked.

It may be in need of reaming to make it a true 5.56.

This is a longstanding problem with BMI barrels.

[Robb Jensen]

Be sure the ammo doesn't pop primers in other rifles, if it does very likely it isn't your gun it's the ammo. If it doesn't pop primers in other rifles then you'll likely need to ream the chamber with a 5.56mm neck and throat reamer from Ned Christiansen, actually this was why he invented it.

[GONIF]

YOU DON'T WANT TO USE A REAMER ON A CHROMED CHAMBER. :eek:

[glock40cal]

The new barrel is indeed a bushmaster installed by their facility.:( I'll try it in someone elses rifle.

[ST911]

YOU DON'T WANT TO USE A REAMER ON A CHROMED CHAMBER. :eek:

Sure you can. BTDT, no ill effect. Ned's reamer sounds like the medicine for this gun.

[scottryan]

What brand is the barrel?

[Robb Jensen]

YOU DON'T WANT TO USE A REAMER ON A CHROMED CHAMBER. :eek:

Sure you can, how do I know? I've seen me do it. ;)
It wears the reamer out a little faster but doesn't harm the life of the barrel. I've done more than 100 chrome lined barrels. Barrel chrome lining isn't like the chrome on the bumper of a 57 Chevy.

http://m-guns.com/tools.php

[sully3acr]

A buddy of mine here at work had the same problem with his RRA. He sent it back and they fixed the problem. Don't know what they did but it shoots fine now. It's not just Bushmaster I've had mine for over 6 years been to Gunsite and some other classes, NO Problems!