lostbackpacker
Hardly any of the new firing pin style can be converted. The ones that used an open breach with a firing block, you don't hear lot about them any more. The Thunder Hawk and the System One as a matter of fact I just seen a System One for sale in The Heber Springs Gun Shop when I picked up my Endeavor, it was a stainless Steel with two barrels a 50 cal and a 54cal. I looked at it would grade it at 85% NRA it had all three firing systems included.
Just in case you might be interested: There phone is 501-362-7000. Lee