Yep its right. You dont have to use BP its still muzzle loaded because you stuff the cylinder from the front.
Whats best. Does your ticket specify caliber they normally do. Look for a full frame for rigidity and avoid a brass frame. That leaves Remmington, Rogers and Spencer or Ruger old army. Depends what you can afford. Ruger should be best but some competitions/clubs dont allow them. Remmi second R/s third.
Colts are open framed so not favourite though some like the notalgia of them. They can go loose and sloppy in use.
“If a cricketer, for instance, suddenly decided to go into a school and batter a lot of people to death with a cricket bat, which he could do very easily, I mean, are you going to ban cricket bats?” :- Prince Philip said after Dunblane