Colt introduced the Series 80 firing pin block in '83, and it is a pretty good, proven system. If you want a 2# trigger, the S80 bits can make a hassle of the trigger job, as you have a few ounces to account for, but for a service type pistol, you'd never know the S80 "safety" is there. Para Ordnance also uses the same system.

The "new" .460 Rowland is essentially the same round as the .451, although if I recall correctly, the .451 was limited to hollowpoint/flat point bullets of 185 grains, as heavier bullets took up too much of the case capacity, resulting in too-high pressures, and round-nose bullets could not be loaded to 1.275" max OAL. I don't know how the Rowland rounds addresses these issues.