Which is the more important consideration, lower FPS velocity or lighter lead payload? ie: 1 oz. versus 1 1/8oz.
Major recoil factors are velocity, payload and gun weight. Note there is no place to input pressure. Generally, if it's easy on my shoulder, it's easy on my gun. If it's beating the hell out oif me, it probably isn't doing my old gun any good, but then, I won't be shooting a lot of them either.
Play around with this using 438 grains for 1 ounce of shot (7/8 x 438 would be 383 grains). Keep your gun weight constant and vary your payload & velocity to see how dissimilar loads compare for recoil. It helps if you already have some idea of your "comfort" level. For instance, I can tolerate 1 ounce @1250 in an 8.5-9 lb target gun for several hundred rounds/day... ~ 15 ft-lbs. I know that going to 1 & 1/8 ounce @1200, an increase of only 2 ft-lbs, limits me to only 100 rds without having it adversely affect my shooting.
http://www.handloads.com/calc/recoil.asp
