Over-pressure or just scuffs?

[MonkTx]

I'm wondering how something in the chamber is causing that curved scratch on a case.

 

[Pawnee Bill]

I consider the cratering from the firing pin hole cosmetic. I wouldn't spend the money for bushing the hole. I have about 20,000 sots in my Rem 700. No problem. If I start to get pressure my first indication is always the ejector hole swipe.

OK. No problem.

 

[Kracken McGraw]

I guess the title says it all.. I loaded some 6.5 Creedmoor, .5 grain below the hornady book max. They fired great, pretty happy with accuracy, no oddness, but the cases look odd to me. Scratches of some sort, and some brown marks on them that I've never seen before.. I didn't have any factory ammo with me to compare, so thought I'd ask the experts here.. is this a sign of anything other than the paranoia of a newbie?


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Do you have a pic of your bolt face? Some of those fired primers have a carbon looking smudge that may be from one leaking sometime. Why not get the firing pin hole bushed? It’s just good maintenance to avoid a problem down the road, most local competent gunsmiths provide this service.

 

[japhar81]

Do you have a pic of your bolt face? Some of those fired primers have a carbon looking smudge that may be from one leaking sometime. Why not get the firing pin hole bushed? It’s just good maintenance to avoid a problem down the road, most local competent gunsmiths provide this service.

Not handy but I'll snag one this afternoon.. I had no idea what bushing was until this thread, now hunting down someone I can trust to do it..

 

[Laurie]

I consider the cratering from the firing pin hole cosmetic. I wouldn't spend the money for bushing the hole.

............. unless you want to move to small primer brass. Mild cratering from the pin/bolt like that in the pics becomes something else with small primers at the same pressures. Primer 'blanking' usually then becomes common and bolt bushing essential.

 

[Ggmac]

watch out for guys like the one in post 12 and 13 . They obviously do NOT know what they are talking about and can really damage a gun or HURT someone. They should be held liable for such BS .
Primer radius looks normal ( would not be rounded if high pressure) fp extrusion is not a fix now or pressure issues. Scratches can be from dirt on a reloading die or most likely from feeding .
Just a heads up , separate your brass as to make . Cases vary in weight wich usually means volume that equals one case can be normal and the heavier ( thicker ) could be excessive.
Gary

 

[BowWow]

I would be much more concerned if the radius around the primers were flattened out AND cratered. I don't see any impressions in the brass from the ejector pin. The length of the firing pin, strength of the spring, headspace can all affect cratering. A sticky bolt is probably the worst sign of overpressure.

The cratering of the primers can..... be a sign of overpressure, but not always. The scratches appear to be from the edges of a magazine.

Federal primers have a softer cup than most other primers, so......it may not be a big deal. Try to buy a box of factory ammo using the same primers.......Ex. If you used federal primers, buy federal ammo. Compare, take notes... If you have a chronograph you could compare the velocity to your reloading data to have an idea. You can usually feel a difference in recoil / sound/ feel if you are overpressure compared to factory ammo.

Excess soot around the case neck can indicate weak loads.... the pressure from the load wasn't enough to make the brass expand enough to make a seal in the chamber. Some soot is normal (your case looks normal to possibly a weak load), a lot of soot is a weaker load.

 

[Doom]

Craters on your primers are pretty much "always" a sign of over-pressure. Back off until they go away.

I'll call BS on that statement.

The straight lines on the case are from guide rails feed lips. IF these are reloads and neck sized they might go away on FLS brass. Some rifles will crater primers regardless of pressure. My Rem 700 308 does and has never pierced a primer in over 1500 rounds.

 

[shoot4fun]

I guess the title says it all.. I loaded some 6.5 Creedmoor, .5 grain below the hornady book max. They fired great, pretty happy with accuracy, no oddness, but the cases look odd to me. Scratches of some sort, and some brown marks on them that I've never seen before.. I didn't have any factory ammo with me to compare, so thought I'd ask the experts here.. is this a sign of anything other than the paranoia of a newbie?


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Scratches are most likely from magazine feed lips and aren't a worry. PLEASE do not try to "fix" that chamber in any way.
DO NOT, for reasons already mentioned in the thread, mix brands of brass. Is that the reason those primers look that way? No would be my answer.
Tell us about the rifle (brand, age, modifications) and a little about powder, primer and bullets used.
It could help better answer your concerns (at least a little more educated guessing).

 

[STS]

Indeed. LOL

 

[ronsatspokane]

I would be much more concerned if the radius around the primers were flattened out AND cratered. I don't see any impressions in the brass from the ejector pin. The length of the firing pin, strength of the spring, headspace can all affect cratering. A sticky bolt is probably the worst sign of overpressure.

The cratering of the primers can..... be a sign of overpressure, but not always. The scratches appear to be from the edges of a magazine.

Federal primers have a softer cup than most other primers, so......it may not be a big deal. Try to buy a box of factory ammo using the same primers.......Ex. If you used federal primers, buy federal ammo. Compare, take notes... If you have a chronograph you could compare the velocity to your reloading data to have an idea. You can usually feel a difference in recoil / sound/ feel if you are overpressure compared to factory ammo.

Excess soot around the case neck can indicate weak loads.... the pressure from the load wasn't enough to make the brass expand enough to make a seal in the chamber. Some soot is normal (your case looks normal to possibly a weak load), a lot of soot is a weaker load.

What he said. Over pressure, for me, has always been characterized flat primers AND primer cratering. As he said, if anything those sooty necks indicate lighter loads.

That said, what others said about bushing your firing pin might be needed to get rid of that kind of cratering.

 

[JSH]

If the scratches don’t seem to come from feed lips, I have seen scratches come from dragging on the inside of the action before ejection. May a burr or sharp edge the ejector is pushing the brass to the outside towards the port.
I had an action that was just chewing up my brass. I finally took the ejector out and pluck them out with my finger.

 

[BoydAllen]

I'll call BS on that statement.

The straight lines on the case are from guide rails feed lips. IF these are reloads and neck sized they might go away on FLS brass. Some rifles will crater primers regardless of pressure. My Rem 700 308 does and has never pierced a primer in over 1500 rounds.

Excellent advice