Cratered primers. What's the deal?

C

Claybuster

New member
After getting back from the range yesterday I discovered that all the spent cases had cratered primers and didn't
look like they had been struck hard enough by the firing pin. They were all Fed primers and all the same whether
light or max loads. Is this a problem with the firing pin not hitting far enough or hard enough or a head space problem? Any ideas would be appreciated.

John
 
The fact they fired tells me the firing pin is long enough.

The firing pin hole in the bolt could be oversize. Got a picture?
 
A picture would help, cratered means differant things to differant folks. could be oversized fireing pin hole in bolt that allows materiel to be forced back into it on recoil,Fed has had soft primers from time to time,normally a "cratered"primer is a indicator of a too hot load.
 
I don't think it's too hot of a load because they all look the same and some aren't up to max. The indentation hole that the firing pin made looks shallow.
 
If the edges of your fired primers still have a radius (not sharp edged), it's a pretty good bet you have an oversized firing pin hole. I have a Rem 700 VLS in .223 Rem that's cratered every primer it's fired, regardless of the load.

Mike
 
It is a Rem VLS in .22-250 shooting 55 grain VMAX with
36 grains of Varget. The edges of the primer still look round not like they've been flattened by a high pressure load.
 
Like my first post said, it is probably an oversize firing pin hole or Rem beveled (de-burred) the firing hole at the bolt face.
 
Quote:
It is a Rem VLS in .22-250 shooting 55 grain VMAX with
36 grains of Varget. The edges of the primer still look round not like they've been flattened by a high pressure load.



The Hornday 6th shows the max load for the 55gr Vmax as 34.6gr Varget, although the Lyman 48th shows 37gr max.
 
Can anything be done about the firing pin hole or is it not that big of a problem? I was going by the Hodgdon manual that shows 36.5 of Varget as max.
 
That data is for the 55gr Speer SP, what was your start load? Hornady shows 30.8gr start with a COL of 2.350", Hornady brass and WLR primer. If you didn't start low enough, I'd work the load again before suspecting the bolt issue. Hodgdon's start load is .6gr shy of Hornady's max, Lyman gives you a little leeway with 34gr start and 37 max in Win brass, WLR, COL 2.345".
 
I have a remy in .223 that shoots 1/2" groups and it produces cratering in the primers. I was worried about it to at first, but if it shoots good and your not seeing signs of high pressue I wouldn't worry about it.
 
It can be fixed by machining the boltface enough to put a bushing in. I wouldn't waste my money on a bushing. Used primers are the part you throw away, who cares what the look like. As long as the outer edge of the primer has a little radius the pressure is acceptable.
 
Thanks Dan. It's shooting good groups with both Varget and Benchmark so as long as there isn't any pressure signs
I won't worry about it. I might try a different primer
and see if I get the same results.

John
 
Just because your primers aren't flat doesn't mean your not at top pressure already. You may notice that your primers are getting loose after only 3 or 4 reloads also. So keep an eye out for that to.
 
Back
Top