Firing pin size in relation to primer size.

[TAJ45]

I need to be schooled on this. I've read info off and on but don't have it in one sock yet. About a third of my rifles have bushed FPs. I'm getting an XC using Palma brass put together so will be pushing the envelope looking for a fast, accurate node at or above 3100 with the heavy, heavies.

 

[Shaggy357]

I think everyone is waiting for the actual question........

 

[TAJ45]

Okaaaay,
What are the effects of a large fpin compared to slightly smaller or std sized smaller fpin when loads are being pushed. I've read of slightly smaller, iirc maybe .005" in competitive builds, radii tweaks.
Looking for general to specific info, facts, even anecdotals.
Cratering, flattening leading to piercing would fall into my question as well.
Causes that can be custom smithed out of a build. HTH

 

[BoydAllen]

Generally, the smaller pin will actually outperform the larger when they are used for hot loads. Jerry Stiller was one of the custom first bolt action manufacturers to advertise a small pin tip. I have shot one of his Vipers since the late 90s. From time to time I have tested some very hot loads and have never had one pierce a primer. If you are running hot loads, make sure that your firing pin spring is up to spec, and I would stay away from light firing pins.

 

[TAJ45]

Thanks, Boyd. I've also read doing a spring replacement periodically is a good idea. Helps consistency.

 

[MagnumManiac]

I have rifles with large firing pin diameters and others are very thin in relation to primer size.
My Kimber 8400 in magnum cases have pin diameters that would suit small primers, they are very small, then I have Model 70's with very large pin diameters.
It doesn't seem to make any difference to performance how big or small the pin diameters are. As long as they are smooth and free of burrs, they all work very well regardless of how big or small they are.

Cheers.