I bobbed me hammer on my GP-100 and no issues with reliability. Spring pressure is what will make it go bang not hammer mass. If the latter was the case then how do all those semi-autos with skeletonized hammers shoot without issue??? Take a look at the hammers that are available for the S&W 686. Virtually half or better of the hammer has been machined away and they function like a raped ape.
NRA Life Member, NRA Range Safety Officer, IDPA Safety Officer, USPSA NROI Range Officer
As you are, I once was, As I am, You will be.