I way prefer m-lok to quadrail (and m-lok over keymod). Quadrail seems so bulky, and really how much shit does one need to bolt on there?Recently picked up a Smith and Wesson Model 57 and a second upper for my MWS308. The S&W 57 was made sometime in 1967 or 1968. .41 Magnum is my all-time favorite revolver cartridge. I used to have one made around the same time period with an 8 3/8" barrel, but I ended up selling it to make ends meet. This one has a 6" barrel, and I think it balances in my hand better than the longer one did. I'm going to get some nice custom grips made for it, possibly in giraffe bone.
The new upper for my MWS308 has M-Lok slots instead of the integral picatinny rails machined into the hand guard like the original upper does. I'll be setting up the new upper with a 16" stainless barrel, Aimpoint or ACOG, weapon light, and not much else. It'll be kept simple and light as a general self defense rifle. The original upper (the one with the Elcan scope mounted on it) will be set up for longer range shooting, so it'll get a 20" stainless barrel, bipod, weapon light, and possibly a laser aiming device and a small red dot on a 45° mount for quick close up shots. That way I'll have one rifle that can fill two roles simply by swapping uppers.