My Colt New Service made in 1906 shoots .452" diameter bullets very well. In fact, I had planned to open up a Lee Mould for this gun -- even had the grit set up -- but decided to shoot it first. It grouped so well that I decided not to fix what ain't broke.
This same gun (with 7 1/2" barrel) shot about a foot and a half high and a foot to the left at 25 yards. Since it had been refinished and the markings almost polished out, I decided to replace the razor-thin front sight with a thick slab of steel, which I filed to get elevation, and then opened up the rear sight notch to correct the windage. I can sit on my porch with this gun now and punish a gallon can on the bank of my pond about a hundred yards away.