Ive been running a gen3 - 20, with 22# springs a 6" barrel and only shoot 200 gr. The load is published and shows 1275fps @ 12 ft. The recoil seems less objectionable to me than a heavy Ruger 357. The Ruger with the fire breathing H110 loads leaves your hand feeling like you've been catching a baseball barehanded. The 10mm with the same horsepower is a firm push no doubt, but to shoot a box full would be boringly comfortable.