Thread: Stirling Model 20 .22LR rifle - maximise buyback price.

Originally Posted by mimms

Tool steel is pretty hard... Unless they've annealed them to machine, why would they need hardening??

Mark told me the tool steel is better steel than the steel used for the original firing pins (hence them breaking).

It may well be that these unhardened tool steel firing pins will outdo the originals. Especially, as you will note from the photo, since he has properly radiused the weak spot on the inside corner to spread stress. I guess this is the common break point of the factory ones.

From other dealings I've had with Mark he's the type of engineer who'll only turn out the best or not at all, and his recommendation was that for long term use he'd harden the firing pin.