I have a pair of 1st Gen Colts, and, in fact, plan to shoot them in a match this weekend. Both are Cavalry guns - one built in 1880 and the other in 1881. I've had them checked by a well known SAA gunsmith. His comment was - "They'll outlast you. And if anything does break, I can fix it."
So I go out and happily blaze away with BP ammunition. And I take along their partner, a '73 Winchester built in 1888. Soon to be joined by an 1889 Remington shotgun. It's really nice to be able to shoot guns that were actually there in the period we are all trying to "emulate" in our fantasy game.