Firing Pin Travel

[hothead]

Not to start an argument, but I was told by a member of Team Savage F/tr team to set protrusion at .060. which I did. I am shooting very stout loads
in the 308 from the Savage custom shop and primers look good. I'm shooting 155.5 gr Berger's at 3070 fps. just to say how hot of a load it is.
I have no cratered primers. the rifle is shooting awesome. like .4 moa at 300 yards for 10 shot groups.
hh

[BillPa]

Not to start an argument, but I was told by a member of Team Savage F/tr team to set protrusion at .060.

I have no cratered primers.
hh

The pin protrusion has nothing to due with cratering-blanking primers, its a result of the pin to pin hole fit, the tip profile, insufficient spring tension to support the indentation, the primer cup or a combination of them.

Sharpshooter has (tried?) educated us a few dozen times why less equals more where pin protrusion is concerned.

You, I or anyone else will ever indent a primer more than about .020", the anvil stops the pin forward at that protrusion length regardless if it set longer on the bench.

A firing pin isn't instantly accelerated to X velocity by the spring, it ramps the pin up in speed. Anything that reduces it fall length or restricts it's fall also reduces it's impact energy, that E=M*V thing. Round numbers, with pin set to .060" protrusion the pin fall length is shortened .040" when it strikes a primer whereas one set to .030"-.035" its fall length is only reduced .010-.015" allowing more time for the pin to accelerate thus increasing it's impact energy.


Bill