My information on the USAF guns does not pertain to the mild M-41 load, very weak. The PGU round and possibly others were Plus P or beyond. They were developed after the M-41 proved weak in Vietnam. The Air Force wanted more power.

I corresponded with a project engineer for the JSSAP M-9 program and read the continuing test results in, Soldier of Fortune, which went into some depth on the matter.

I don't claim that Dr. Pig is all wet, just that various factors have to be considered in evaluating whether modern .38 ammo is weaker than it used to be. The change in measuring velocities and pressures is an important factor.

Firing BP ammo from around 1900. with no idea of how it was stored, will not necessarily indicate its true orginal velocity. But I did enjoy the links.

Actually, I asked some time back if standard .38 Special ammo from the 1920's was hotter than now, because I armed a character in fan fiction wth a five-inch barrelled M&P, and wondered what velocity she'd have been getting. I guessed maybe 875- 900 FPS, and that seems to jive with what I can learn. That was with smokeless loads.

I do fire Plus P ammo, and don't think that most is loaded really hot. But if the manufacturer says in a blanket statement not to do it or void any warrenty, I think it's wise to shoot it only in guns with a model number stamped in the frame, as the factory recommends.

Keep in mind that many of those AF M-15's were range guns, heavily used. Also remember that the USAF wanted to make the situation look as bad as possible, to prove to bureaucrats that they needed a new handgun that would deliver the ballistics they wanted. NATO standardization was a factor, but not enough that it hadn't been rejected before. The powers that be just said that there were too many .45 autos on hand to warrant a change to share ammo with allies.
By 1984-85, that was changing, and other arguments helped, too. We got the Beretta M-9.

I hope this clears up what I said. I had rather post on this myself, rather than see here what someone else says that I said.