Primer Cratering

Hippy · 06-08-2013, 08:27 AM

My 6BR is cratering the primers BAD it does not pierce them although it looks like it could--Weak Firing pin spring or ??

Thanx,
Jim

82boy · 06-08-2013, 11:05 AM

There is several things that can cause primer cratering. Yes week firing pin spring could be one of the causes, but from my experience with Savage actions, as long as you have the factory spring in it, and left it alone, then I would highly doubt this would be the cause. Other causes of cratering come from misshaped firing pins, and the firing pin not properly fitting the hole in the bolt head. people start having cratering problems after the blank a primer, because they don't inspect the firing pin shape, and the pin tip can be damaged, and as well as gas cutting to the hole in the bolt head. Having the bolt head brushed would solve this problem. The other causes can be for improper ignition, with the firing pin being short on travel. Changing triggers and other parts will affect ignition, the bolt may be de-cocking as it is closed, limiting the amount of available firing pin travel. Basically the gun is out of time. Other things that can cause this is cutting springs, or placing spacers behind the Back action screw trying to make the bolt open easier, and so on.

With that said, the 6 BR is a problematic cartridge of sorts to begin with. Do to its size, and shape it has problem extracting in a Savage action. The worse problem is where it preforms its best is at the edge of the envelope. Where most people are shooting these at it at the point of overpressure. Most people shoot 30 gr of Varget, on a 105ish bullet, and it is at the point to where it will leave ejector marks, shiny necks, and cratered primers. Most people shoot CCI 450 mag primers and this will alleviate some of the cratering problem, because the primer has a harder cup.

With that all said, if you having cratering problems, start by backing off on your load. If it is still a problem send it off to a quality gunsmith that knows about the Savage action, and is not going to treat it like a Remington, because it is not. Make sure that gunsmith understands the fundamentals of timing, and is familiar with Benchrest calibers.
With that said good luck.