Thread: 45-70 firing pin diameter

My google skills have let me down this evening.

I'm after some real world data on .45-70 ( or similar old school 40k psi cartridge ) firing pin diameter and protrusion ?

I have an existing firearm that I will re barrel in 45-70 and pressure will be around 40k max

The existing firing pin diameter is 0.083" in good condition and reasonably tight in its hole.
Protrusion is around 0.060"
This is a firing pin that will seal off the gasses at its base if there is a ruptured primer so gas will escape across the breech face rather than back through the action

I know that a modern firing pin for something like this would maybe be 0.070" diameter.

Just wondering if anyone has any useful info on this subject ?

Apologies for the inches ... but the more I dig into these old guns, the more I find myself having to use inches and fractions rather than metrics