Dig, Dig, Dig,
This is the trouble with you young, fit types. At my advanced age and, given my fast-deteriorating muscular and nervous systems, I find that I need a light gun to keep up with whoever's trying to poach my birds. (To say nothing about poaching his!) I have a pair of 20 bores that weigh in at 6# 2oz and a pair of 12s (2 1/2") at 6# 4oz for driven. These work for me. As for heavier ones, I have sold off my heavier sporting clays guns and now use only 20 and 28 bores. Same reason. I can get them moving sufficiently quickly to have a hope of getting ahead of the bird. I may miss a fair number, but at least I hit some. With my old 12 bore Perazzi, it was getting really depressing!