Forgot to indicate that that I had the 632 barrel also, but it's marked "Airweight" as well. Don't know if I should switch both out, giving me what amounts to a 631 2" weight-wise, leave the current barrel & make a 3" fixed sight .32 Magnum pinto (cylinder only), or get a 4" 30/31 barrel and make a fixed sight 4" and call it "M&P Mini-Me". Somehow, I think a 3" 32 Mag would be a fun little gun with a little more umph.