OK let's solve mystery ,to me, #2.

I posted a picture of the two model 64's with different frame sizes. The answer was the the frame mounted firing pin caused a need for extra frame length. I just compared my 66-2 and my 617. Exactly the same frame demensions.

Explain that to me. Why are mine the same and my friends different.
I'm on a learning roll here. Don't stop now! ha ha

John