I just picked up a Safety Harbor upper and after getting it set up I let my Son In Law fire the first two rounds and he says it hurt, pretty bad. Now he's not small by any stretch, 6-2/320 so he's a pretty good size boy. I didn't shoot it so I'm taking his word for it and he's done this before so I'm thinking this thing hurts. The brake is nowhere near as big as the AR-50 or a Barrett so I'm thinking about trying a different brake, any suggestions?

Maybe he's just a pussy . No seriously though, I always hear guys say they're big so recoil shouldn't bother them. The fact is the bigger you are the less you will move with the recoil and the more you absorb the recoil and feel it(kind of like a leadsled). Little guys roll with the blow.

Any 50 will kick regardless of the brake. My 50 has a fishgill style brake, it's effective, I like it and it doesn't stick clear out to the sides like the clamshell style brakes.

Maybe just whup on that big boy a little more until he increases his pain threshold or buy him a rimfire.

I'd try it yourself, like filmit says, the bigger guys take recoil more to the body. Also, everyone is different and the gun may fit you better.

WIth a .50 it's the combination of weight and brake. I have a three-chamber baffle-style brake on mine. Of course I'm also using a full-size M2HB-barrel and the damn gun weighs about 50 pounds, heh. Anyhow you might want to try a different brake as those S/H uppers aren't real heavy.

Two cents here, because we're still laughing about it.

My nephew and I went to the range a while back. Moving down to the firing line, one of the shooters remarked, "You might want to set up farther away from him. He's going to shoot the 50 in a few minutes."

Yeah, OK. And so we moved a ways down the line to an open bench. But we left a stack of targets on the bench next to the guy with the 50 cal. a Barret with the "standard" three-baffle brake on it.

BOOM! One shot and the stack of targets on the adjoining bench flew into the air like they'd been hit by a cyclone. And I went back up to the office to grab a pair of ear muffs to add to the orange foam plugs in my ears. Not since the mortars in the infantry.

The AR-50 break and other breaks that are similar are about the most effective breaks out there. They are certainly more affective than the Barret type of breaks.
As mentioned though, the break on the AR-50 will clear the bench next to you, but the recoil is a shove, not a jab. When I got mine my son could not wait to shoot it. He was 14 or 15 at the time and was use to shooting my big bore rifles and while he was anxious, he approached the .50 with some trepidation. One shot and he was sold. He could not believe how mild the recoil was, being much less than our turkey shotguns or any of the big bores that he had shot.