Positive they are new, in a sealed Peterson box.
Thoughts on this please
- Thread starter Philward
- Start date
Help Support Long Range Hunting Forum
Wow. Has to be a rifle related head spacing problem or a defect in the brass ductility, and Peterson has a good reputation.
I use only it and Lapua myself.
Id check headspacing for sure.
Same here, I had Willis die for a decade and never used it through half a dozen 7 mags, custom, and factory.
Lots of NONSENSE keeps getting repeated on the net about belted magnums. If a Non Truth is repeated often enough, then it is accepted as truth.
I would have the OP's chamber inspected by someone that has a bore scope. as it looks to have a scratch in the chamber.
On many chambers, if you only bump the shoulder back .002, you may not reduce the dia in front of the web enough to chamber the round when the case needs full-length sizing. Often you have to bump back the shoulder quite a ways so the case is actually full-length sized. When you have no choice you will get a bit of case stretch where the case may have to be discarded after 8 firings or so.
I started reloading the 7 mag and 300 Win mag in 1978 and never had a problem with belts in Rem 700s, Savage, Browning, and customs. Guys that are NOT advanced reloaders that have problems with a belted magnum, always blame the belt when it is their lack of knowledge that is really the problem...production dies and factory Chambers. Small base sizers per caliber often solve a lot of problems as mis matches between Factory chambers and production dies vary greatly.
The problem in the OPs chamber looks like the reamer picked up a chip that scored the chamber, and with a small mini mag flashlight with the bolt open, if you spin the rifle around on the muzzle, look in the chamber, you may actually see the imperfection. I am assuming that the scored section on the brass happens on every case in the same place, no matter what brand of brass you use.
If you have a headspace problem, often a ring will start manifesting itself partially around the circumference of the case. Some think that a "case stretch" ring will go all the way around but that is not the case many times. Then the case will separate on subsequent firings. You will extract a case head, insert a pistol cleaning brush into the part that is stuck in the chamber, and the case will come out with no effort exerted.
You should quickly and with little effort be able to determine if the chamber is scored with the small flashlight.
Last edited:
If you had case head separation previously, yes, you can have a carbon buildup in the chamber that will mark your new brass. Been there.
A good carbon removal should fix you up.
My stw brass moves .018" after the first firing and I don't get heads coming apart once I learned how to bump the shoulder.
A good carbon removal should fix you up.
My stw brass moves .018" after the first firing and I don't get heads coming apart once I learned how to bump the shoulder.
Bob, it would be wierd to have carbon build up just in front of the web, but anything is possible while we try and brain storm to help the OP. I have seen a bunch of rusted chambers, but we can only guess.
As I look at the photos again really closely I notice the ring is not 360 around the whole case, so it may as you suggest be some defect in the chamber scoring the case only in one place likely when it is rotated and extracted.
The mark is only about 40% around the circumference and is at the exact location as the case head separation. Had to use JB weld stuffed into the case remnants in chamber to remove it. I don't recall is the mark was there before that happened and I cannot attest to how well it has been cared for, not my rifle. Now was the mark there when new and it contributes to case failures or at least will contribute to future case failures by weakening that area of the case? I was concerned with the previous cases when they started showing marks like this and I figured it was a stretch mark due to oversizing. Rifle still shoots well. Then the case head separation happened so I told the owner need to get new brass and sorted the loaded rounds, separating out the ones I thought might be impending failures. Told him not to shoot them. I pulled bullets on a couple of them and checked the case inside with bent paper clip and they were fine (?). So I reassembled and they were fired without issue. But one of the other ones I fired to shoot them up partially separated so I quit shooting them, took the last 6 apart and discarded all that brass. The case in picture is one of the 100 Peterson he bought at my suggestion when they were available last fall I think.
I was mainly curious of the case separating could cause pitting or damage to the chamber and that is what is causing the mark. I don't use cleaning solutions that are harsh enough to damage the barrel, I don't think I do anyway, maybe he left something in there after cleaning.
I was mainly curious of the case separating could cause pitting or damage to the chamber and that is what is causing the mark. I don't use cleaning solutions that are harsh enough to damage the barrel, I don't think I do anyway, maybe he left something in there after cleaning.
cdherman
Well-Known Member
I think this would be a good $56 spent.
Teslong Borescope
Might be some remnant JB weld. Find out. I think a 20 gauge brass bristle might be the right size to clean up a 7 mag chamber.
Teslong Borescope
Might be some remnant JB weld. Find out. I think a 20 gauge brass bristle might be the right size to clean up a 7 mag chamber.
I feel like there is a simple answer. It may not be the answer you want, but the bore scope is sure going to eliminate a lot of variables.
QuietTexan
Well-Known Member
Because reamers have tolerances like anything else. All it takes is getting a chamber cut with a new tool vs a worn tool. Factory will always lean on the side of being long enough and not too short. The shoulder portion of the reamer cuts a lot more metal than the belt portion does, 10x moreso if they aren't using carbide roughers.
There are surprising +/-0.003 variations between "identical" reamers pretty often. Throats are the most likely place to be off mainly, those can be full 0.010" or more off.
This whole mess looks like normal tapered inner wall case fitment to me. Same thing like the lines I get on my 30-06 above the case web.
Last edited:
Not really hot, 64.9g IMR4831 nos 168 ABLR Vel 3003. Also recently tried 7828 and 7977 because that is what I had on hand and didn't have IMR4831. With the Peterson brass I backed off the powder to 64. I have just got an 8# of IMR4831 since the rifle seems to shoot well with it.
best defense
Well-Known Member
All good advice, also before you bump the shoulder back, anneal the neck and shoulder so any streching should be up at the shoulder and not back at the web.
