I had some misfires with .45 auto rimmed, where I can find a longer fire pin. Hope could help.

i had the same problem with my thunder ranch 45 acp revolver, i got a longer pin from brownell's but it did not help. i had to turn a few thousands of the under side of the main spring strain screw as it was not going in far enough.
after that it worked perfect with the orignal firing pin.