Blown primers with 7.62 not .308

[Bullet_magnet]

Hey everyone, was out shooting my new to me Remington 700p LTR in AICS chassis.

Ran both 175 grain .308 gold medal match and GGG M80 Ball 7.62.

The M80 ball ran terrible. As you can see, popped primers and stuck in the chamber that I needed a rod to get it loose. I also had a round get so stuck I do tap the bolt with a piece of wood to loosen it up.

I contacted the vendor of the ammo who thinks the rifle has a headspace issue. However, once I swapped over to that gold medal match, everything worked just fine.

Wanted to ask the folks on here that would know better than I might.

If anyone is wants to see pics of the federal brass...just let me know!

Thanks!

 

[Mike Casselton]

That junk ammo is junk. It's a headspace issue with the junk ammo.
Junk it.

 

[alamo5000]

5.56 vs .223

With this caliber though it's exactly opposite.

.308 is the higher performance one out of the two.

 

[B y r o n]

Since 7.62x51 is rated at lower pressure than .308 Win I'd say the GGG ammo is loaded hotter than .308 Win spec.

 

[Bullet_magnet]

Appreciate the quick replies gents.

The vendor states:

If there were a pressure problem with this lot of ammo I would have known 3 months ago. 762x51 should interchange and work as normal, and I know its not the ammo.

This is from a well known retailer...but I'm a bit newer to bolt guns so I'm a bit ignorant as I've mostly just owned ARs.

 

[B y r o n]

So how do they explain the primer being blown out of the primer pocket, despite the crimp around the primer?

 

[papershredder]

If you still have an unfired round, measure it, chamber it, then measure again to see if the projectile is getting pushed down in the case. 7.62 nato does headspace a little longer than .308, so if your rifle has a tight .308 chamber, you can run into problems with nato ammo.

 

[Mike Casselton]

If the ammo was longer, the primers wouldn't be backing out. The headspace on the shit ammo is too short.
Ditch it

 

[supercorndogs]

The headspace is too much. I couldn't tell you if its your chamber or their brass. I would suspect their brass is too short if it doest do it with the other ammo. If it does I would suspect your chamber is too long.

What your are seeing is not blown primers. It is the primer backing out of the case fro excessive headspace. Blown primers are different animal, you will find the primers stuck in your gun, not stuck in the case.

 

[Bullet_magnet]

The headspace is too much. I couldn't tell you if its your chamber or their brass. I would suspect their brass is too short if it doest do it with the other ammo. If it does I would suspect your chamber is too long.

What your are seeing is not blown primers. It is the primer backing out of the case fro excessive headspace. Blown primers are different animal, you will find the primers stuck in your gun, not stuck in the case.

I'm learning stuff already! All signs point to ammo it looks.

 

[PinesAndProjectiles]

Do you have the ability to measure the datum on the case shoulder both on the new brass and the fired brass?

 

[Bullet_magnet]

Do you have the ability to measure the datum on the case shoulder both on the new brass and the fired brass?

How would I do that/what tools do I need?

 

[papershredder]

How would I do that/what tools do I need?

Digital/dial calipers with a case length gage or an optical comparator. What you can do if you don't have access to those tools is get one of your unfired nato rounds and stand it up next to a fired FGMM case on a flat level surface (if you want a control, the place an unfired fgmm bullet on the other side of the nato bullet). Make sure the cases are side by side and take a clear, close-up picture of the shoulder area of the two (or three) cases. What we are looking to see is if there is a noticeable visible variation between them. If there is a visible difference between the shoulder heights from the base, then that will at least clue you in to where to start looking.

 

[PCR]

Mike Casselton gave you the answer