You can forget about the diamondback and police positive. The trooper MKIII will probably be the most common, then the officers model match. If you include single actions then the scouts, peacemakers and new frontiers will be very common with extra cylinders for 22 magnum which is more useful as when prices get back to normal, 22 mag. ammo if about 5X as much as 22LR bulk. I was just shooting my scout with 22 magnum as I lucked out and found a 22 magnum cylinder at the big Louisville show for $20 and it works fine.