I wonder about that. I have a M60 Talo .38 Special, and a M60 .357. The cylinders are identical. I have often wondered if S&W simply grabbed a bunch of cylinders from the M60 bucket and chambered them for the .38? In which case it would take a lot of stupidity to over dose the gun with any .38 ammo.
Old thread. I guess we're all spending more time surfing these days!
I've opined on this here before, and that's definitely all it is, I have no inside knowledge.
At the time S&W first fielded these guns, the "latest and greatest" ammunition for the .38 Special was the Federal 38HS2G. That was the 147 grain Hydra-Shok. It was the FBI's last .38 load and had been designed to meet their then new and developing penetration/expansion models.
It was rated by Federal as +P+.
The loading was not especially hot, but that's how they listed it. Maybe because that was still the era of, "For Law Enforcement Use Only" and the +P+ went along with that. Who knows?
My belief is that the, "Rated for +P+" on those early M640s was directly related to the 147g Hydra-Shok.
S&W could not field a brand new, law enforcement oriented revolver, that couldn't handle the then-current FBI load.
Soon thereafter, the FBI (and everyone else in law enforcement) moved on, and Smith dropped the +P+ markings to avoid sanctioning something that had no true definition anyway.