Issue with Federal GMM brass

[guncrazy72]

Hey everyone. I have a weird issue going on while trying to reload some factory GMM 308 brass. Some of the brass de-primes and resizes fine but the rest of it only de-primes the center of the primer and leaves the rim of the old primer in the primer pocket. Ive never seen this happen before and figured the brass is now trashed. I tried to pull one of the left over primer rims out with a flat head and screw driver and they wouldnt budge at all. Anyone else run into this issue before?

 

[High Binder]

rim of the old primer in the primer pocket.

The "rim" as in it punched out the bottom of the primer and left the sides? Or do you mean the anvil is still stuck inside the pocket?

 

[Graham]

Crimped primer pockets?

 

[guncrazy72]

The "rim" as in it punched out the bottom of the primer and left the sides? Or do you mean the anvil is still stuck inside the pocket?

It punched out the bottom of the primer and left the sides in the primer pocket. Everything else came out fine.

 

[mdmp5]

Are you saying that your decapping pin has actually punched right through the primer, putting a hole in it? Almost hard to believe. It's not like decapping pins are sharp as needles or anything. Can you possibly post a pic of your case heads that this has happened on?

 

[KYpatriot]

Check your decapping pin, did some of it break off into a sharp point?

 

[guncrazy72]

Here is some pictures of one of the pieces of brass.

 

[guncrazy72]

Check your decapping pin, did some of it break off into a sharp point?

I did. This is a brand new RCBS die set. The very first piece of brass I de-primed did this. Out of 50 pieces I de-primed and resized I only had 15 that I could use that did not have this rim left in them.

 

[High Binder]

It punched out the bottom of the primer and left the sides in the primer pocket. Everything else came out fine.

Wow, I've never see that, sounds like the primer cup was weakened (or weak to begin with). Assuming their not crimped like Graham mentioned, you might very well have some scrap brass on your hands.

It's clearly going to be what we call an interference fit as FGMM shoudl be clean brass to start with. So my only suggestion would be to try heating the web portion of the brass up in boiling water and prying the cup sides out.

If all else fails I have stack of FGMM once fired that I don't use...

 

[High Binder]

I don't see the sides of a broken cup in there. Are you sure you're not just seeing the offset step in the brass? Did you double check the punched primers to make sure that the sides aren't still attached? I zoomed up on the image and all I see is the normal purple step.

 

[mdmp5]

That brass doesn't look crimped to me, unless the crimp is what you circled. As stated above, try to show us some of the punched primers as well

 

[Sevo2300]

I agree with High Binder, it is tough to tell if the pics show a crimp or the residual rim of a primer. I have popped the "base" of the primer off, leaving the rim, in crimped 9mm with sealed primers that was wet tumbled before decapping. If you are indeed leaving the walls of the primer behind, I found that breaking the sharp edge of the decapping pin will help.

 

[FLIGHT762]

I don't see the sides of a broken cup in there. Are you sure you're not just seeing the offset step in the brass? Did you double check the punched primers to make sure that the sides aren't still attached? I zoomed up on the image and all I see is the normal purple step.

I agree. I think you're seeing the primer crimp. I have had decapping pins punch through the center of a primer and leave the sides of the primer in the primer pocket. I just had one in a 5.56 case last week. Most of the time, this is caused by a case sitting out in the elements in the rain for a long time and corrosion causes the primer to corrode and adhere to the pocket wall.

Can you show a photo of one of the primers that have been removed?

 

[guncrazy72]

Thanks for the replies. I will go and take some pics of the old primers. I only found this after I tumbled 20 of them to do some test loads. After tumbling them I went to prime a few and the primers wouldnt go in at all and with slight pressure would begin to really mess up the sides of the primers. I will post some pics soon.

 

[ArmyJerry]

Looks like its crimped, might want to decrimp he pocket and get a pick and remove the debris, strange one though.

 

[Jimichanga]

Crimped primers.

I think you are looking at the difference between FGMM .308 vs FGMM 7.62x51. The 7.62 FGMM is crimped IIRC. Try to buy FGMM 308 if you can find it.

 

[KYpatriot]

Yeah that isn't the normal 308 FGMM head stamp...and I don't see any walls of the primer cup in there. Ream or swage it and you are gtg.

 

[guncrazy72]

Crimped primers.

I think you are looking at the difference between FGMM .308 vs FGMM 7.62x51. The 7.62 FGMM is crimped IIRC. Try to buy FGMM 308 if you can find it.

This is the answer right here. I completely forgot that I had shot some of the 175gr 7.62x51 GMM and the regular 308. I went outside and checked and all 15 of the ones that I was able to prime and load were the 308 head stamp. Figured it out! Luckily I do not have much of the 7.62x51. Thanks again everyone! None the less, heres the pictures comparing the two.

308 on the left and the 7.62x51 brass on the right

 

[FT308W]

Crimped primers.

I think you are looking at the difference between FGMM .308 vs FGMM 7.62x51. The 7.62 FGMM is crimped IIRC. Try to buy FGMM 308 if you can find it.

Yep, I was about to post the same thing. Good info here on differences between FGMM 308 and 7.62x51: http://www.snipershide.com/shooting...o-rifles/106176-fgmm-308-vs-fgmm-7-62x51.html

 

[ArmyJerry]

Still though I never has a problem decapping a crimped primer, strange.

 

[guncrazy72]

Went out and sorted all my of GMM brass and found 7 more of them that are crimped. You can see the crimp well while looking at the primer. I deprimed 150 of the actual 308 GMM brass with zero crimp ring left. Luckily I am reloading only now so no worries about the crimp any longer.