Why is this happening

[duman444]

I have 2 guns in 10 mm, a 610-2 and a RIA 1911. Took them to range last week and the 610 cylinder was jamming between shots. Would have to give it a smack with a hard plastic ammo box to unlatch cylinder then it would go back in and rotate normally. Noticed about 5-6 dark primers. The 1911 shot normal-no issues with it. When I got home and was cleaning the guns saw the damage to breech face on both guns, but the 1911 may have been there for a while.

Checked the primers, they have a tiny crack in the bottom of the pin indention. Did not save any or get pictures. I am running 8.4 gr of Power Pistol over Remington 2 1/2 large primers with a 180 gr plated flat tip bullet. My Garmin was clocking the bullet at 1,150 FPS out of the 4 inch barrel 610 and 1,160 out of the 5 inch barrel 1911.

I assume the 610 was "spot welding" the primer base to the recoil shield, but seeing as this load is almost a full grain below max, not sure why this is happening?

 

[JohnHL]

Primers not sealing tight in the cases and leaking hot gases?

John?

 

[stansdds]

Oversized primer pockets?

 

[duman444]

I had to buy a bench mounted primer seater to seat the Rem 2 1/2 primers. They are all in TIGHT.

I bought 10,000 of the primers on the last sale when they were under $60 per K. Have used them on 45 colt hot and medium loads, 44 mag med, 44-40 and 41 mag med loads. Have used 3K and the 10 mm is the only place I am seeing this issue.

 

[Snapping Twig]

The disc that surrounds the hammer nose in the image is... completely gone. Must replace.

 

[WR Moore]

Checked the primers, they have a tiny crack in the bottom of the pin indention. Did not save any or get pictures. I am running 8.4 gr of Power Pistol over Remington 2 1/2 large primers with a 180 gr plated flat tip bullet. My Garmin was clocking the bullet at 1,150 FPS out of the 4 inch barrel 610 and 1,160 out of the 5 inch barrel 1911.

but seeing as this load is almost a full grain below max, not sure why this is happening?

First, you mention that the primers have a tiny crack in the pin indent. Check your firing pins, the ends are supposed to be round, without sharp points. If you've got a crack in the primer indent, you have gas leakage that's eroding the breech face. May be a defect in the primer cup material that's allowing perforation of the cup. Just as a start, if your pin noses are properly shaped, you should try another brand of primer. I've used that same load (varies a bit 8.22-8.4 gr) with WWLPs and XTPs without issue.

Also, just because the load data is safe in the load manual doesn't mean it's safe in your particular gun. Those case head markings on the recoil shield suggest things aren't business as usual. My 70's era model 28 doesn't have marking like that.

 

[rockquarry]

I have a pre-war Model 70 Winchester that I bought in 1964, my first rifle. Still have it. It's been fired a great deal, especially after having it re-barreled and chambered for the then-wildcat .25-06 in 1965. Somewhere along the line, the hot handloads of a new handloader slightly pitted the bolt face. Primer leaks, I suppose. Recommended balls-to-the-wall loads were a bit warmer than today and they were not pressure tested.

The harm was done, but it seemed to have had no real effect on anything. I still shoot the rifle occasionally. If pitting is really bad, I think most bolt faces can be bushed.