ACP too hot?

[gmerkt]

No over pressure signs.

.45 ACP is a fairly low pressure cartridge. By the time you see primer deformation, you are already well past maximum.

The .38 Special of old, 20's to late 30's, have greater velocity that they do now. How do you explain why the older .38's were more powerful/faster that new.38's

It wasn't until well into the 1960's that jacketed bullets were typically offered in civilian .38 Special ammunition. So those loads of the 1920's and 1930's were all cast bullet rounds. Which results in lower pressures.

Comparing "then and now," I submit the following:

Phil Sharpe's book, 1937. 158 gr. lead bullet load, 3.0 gr. Bullseye, 790 fps.

Speer #15 manual, 2018. 158 gr. lead bullet load, 3.1 gr. Bullseye, 752 fps. Top load, 3.5 gr. Bullseye, 814 fps.

So comparing these two sets of data, not too much difference. Without considering there might be minor differences in the composition of the powders then and now. Which there may be. And the usual variations that exist from one reference to another. Temperature, altitude, cast bullet composition, etc. And when I say, "cast" bullets, they might be swaged as some factory lead bullets are. Which tend to be soft.