Shotguns are easier to regulate and are more forgiving in using multiple loads because of pattern overlap. Unlike a double rifle that has to group pretty closely together shotguns only need to have a reasonably good amount of overlap in the pattern to work effectively.
For example; if a shotgun is regulated with say 1oz of shot and has 85% overlap in the pattern and you shoot 7/8oz shot and you only get 65% overlap in the pattern, that's still more than enough coverage to be effective. Whereas in a double rifle changing loads can have a drastic effect on groups.
It's not that you can't run multiple loads in a double rifle it just means you have to spend the time to work up loads that will all regulate to the saem point of impact/point of aim. I have a 450-400 3" Nitro Express that I have 3 different loads for. It is regulated for 400gr Woodleigh solids at 2150fps and shoots 2" aggregate groups at 50 yards. I have a 185grJHP load worked out for it that will shoot 2" groups at 50 yards and a 300gr soft point load that will shoot 2" groups at 50 yards. The 185 and the 300's were done by varying the powder and velocity until I found the right load that would match the lighter bullets to the regulation of the rifle. It can take a lot of range time and reloading and can be frustrating at times but if you don't want to shoot whitetail with 400gr solids it's nice to have the lighter loads developed.
Colin
Last edited by CowboyCS; 06/02/13 09:51 PM.
