ClemBert, I'm pretty sure a Pietta Remington will be a drop in.
As far as reliability is concerned, it all has to do with unnecessary internal forces the hammer has to overcome. With the ham-handed, crude parts in the reproduction revolvers, it was easier to remain profitable just to "overpower" the hammer than to make more refined action parts . . . as witnessed today by Uberti's most excellent parts and lighter main springs. I just had a conversation with a customer that has won 2 State championships and two international championships with a pair of Remington's I set up for him 3 yrs ago. His revolvers have a 4 lb. hammer draw (my standard for cap guns). The action of course is sprung with coil torsion springs and heavily massaged parts. My point being, a cartridge revolver doesn't necessarily need more than a 3 1/2 lb hammer draw to pop a primer and likewise, a cap doesn't need more than 4 lbs . . . certainly not 6,7, or ,8 + lbs.
With a competition revolver in a timed event, moving a 4 lb hammer is much more conducive for winning than a hammer that takes twice the effort to move. And, reliability is a priority!! It's true that the originals were made mostly for military. That's not what our reproductions are needed for today and I would submit that competition revolvers today see much more action than most all of the originals saw. Therefore, why would anybody rather fight with their revolver just to "enjoy" it when they could handle them just as easily as a cartridge revolver . . . and just as reliable?
Mike