you'll need to silver solder a stop on the front of that pin.
It needs to hit the back of the striker before the firing pin protrudes until the rollers are out and locked.
The original pin length plus .44" works for all my builds.
I can't believe anyone would still be selling such a dangerous design still after years of having a safe design free to copy. Is this pin old?
my old posts the designs should still be here. be safe