I personally think the stainless barrel throat resists erosion better, and Winchester used stainless barrels as far back as the 1930's in Model 70 rifles chambered for the .220 Swift cartridge, which had a tendency to erode barrels quickly.
Back in the 1980's one of the gun mags did an article on stainless, and the author said that factory engineers had told him that S&W stainless barrels stood up better. But that might mean primarily that the rifling endured better. I wouldn't run a lot of hot loads with light bullets in either a blue or a stainless K-Magnum.
My M-66-3 was bought new in 1990, and has had maybe 15% .357 loads through it. Based on what S&W personnel told me, I almost never shoot 125 grain or lighter ammo, and stick to the 140-158 grain range. I do have some Remington 165 grain hunting loads on hand, in case I'm ever in bear country with just a .357. The slight weight difference over the 158's doesn't make the difference; the heavier bullet is supposely structured to provide deeper penetration in deer and larger animals.
I asked about the 140-145 grain bullets. No one with any of the four ammo companies consulted knew of any specific studies devoted to these, but the general feeling was that they are heavy enough to burn most of the powder before the bullet leaves the case, and that "ejecta" entering the barrel throat would be similar to that from 158 grain loads. However, some of the 140's have been stoked pretty hot. I sort of prefer to shoot them in heavier guns.
But if you need high velocity from a snub or three-inch .357, those 140's will often deliver over 1200 FPS from a three-inch bbl. Worth remembering, although I wouldn't shoot them routinely in a K-Frame or smaller gun. But I don't use ANY full .357 load routinely in these smaller guns. Use them when needed, or for occasional familiarity firing, but normally shoot.38 Special ammo. Your gun, your hand, and your wallet will appreciate that.
The better Plus P .38 ammo and the "medium" .357 loads are ideal for most self defense work in smaller .357's, especially if you might have to fire the gun indoors. Muzzle blast does not make the .357 ideal in enclosed spaces!
In the great outdoors, it comes into its own, and the K-Mags are handy to wear when you only expect to shoot the gun occasionally (if at all) as you go about your daily business. The backpacker, hiker, or cop will find the lower weight and ergonomic qualities of the K-Magnums much to his liking. The dedicated varmint hunter, who uncorks many rounds of .357 ammo a year, may be better served by a larger .357.
I think it goes without saying that the M-66 conceals better than a M-686 or a Ruger GP-100, when that's a factor.
For what it's worth, if I could have but one handgun, it'd probably be my four-inch M-66, although the GP-100 comes in very close. The Ruger might win mechanically, as it will run longer with heavy use and no repairs. If you don't live near a good gunsmith, that has to be considered.
Back to the original question, I always buy stainless hadguns now, for the reason given above by the gentleman from New Orleans.
T-Star
