Your alloy "J" fevolver was designed for use with standard velocity 158 grain RN lead ammunition.
S&W does not advise regular use of +P ammunition. While an occasional firing won't hurt it, constant use of +P jacketed bullet ammo will quickly loosen the gun, give it timing problems, and make it unreliable.
I make it a point to shoot only mild 158 RN or 148 WC lead bullets in my alloy frame revolvers.