Because my Model 15 is the most accurate gun I own. The X wring shakes nervously everytime I break it out at the range. I carry a +P 640 24/7 and have done so for 15 years now, would not trade it for the world. I have no desire to pump .357's through a similar weight gun, done it, don't want to go back there. My K frame carries well and makes a sweet trail gun, great for small to no so small game. As far as .357 goes I have nothing at all against it, it is a great cartridge. Just no debating that. When I feel the need for Magnum type power, I go straight to the .44. In fact the only .357 in my collection is a Rossi 92 Carbine. My Colt Trooper sat in the safe for years once I bought my SBH in .44 Mag. Eventually I sold the Trooper, have not been able to justify another .357 revolver. Would I like one, yes, maybe a 50th Anniversary Blackhawk, but I am afraid it will just sit as well. My 2 cents, Bill.