Mike, I gotta ask. What is the purpose for removal of metal/clearancing of the inside curve of the hammer? I have done something similar when I find there is contact between the hammer and frame. It usually shows up on the hammer as a bright circular spot right where the arbor is staked at the back of the frame. I believe I read where Sam Colt originally designed a bit of clearance on the hammer so its inside curve didn't exactly match the curve of the frame. Either way, I find the extra clearance provides a bit more room so a fired cap doesn't get squished if it lands there and consequently prevents the bolt arm reset which locks up the action.