My security six was the absolute WORST medium frame gun with heavy loads for felt recoil and muzzle climb I've ever fired, bar none, case closed. He could handle it with .38s or reduced loads, but with heavies, it's a hand biter. It actually HURT and I had a Hogue nylon grip on it. When I first put that on, I had to shave the sharp edge off it that didn't quite match up with the grip frame cause shooting it put two bleeding cuts on the palm of my hand. DAMN that thing was bad. My 19 Smith, my Taurus 66s, even my light Rossi 971 and my 27 ounce SP101 were/are WAY easier to shoot. That's one reason I traded that S Six off on a new Blackhawk even up.
No kiddin', with a Hogue grip on the SP101, that thing is NICE even with 180 full house handloads. I'd never shoot those loads in that S Six, would be masochistic to say the least! I really don't miss that gun at all, though it was lighter and easier to carry than a GP100 and a strong action. I'd rather drop a round and gain some concealment and go with an SP101, major improvement IMHO. YMMV, most seem to. Just call 'em as I see 'em, but the SP101 is WAY superior as both a shooter and a concealment gun to the S Sixes.