A "Hot load" is just a term...........

98% of this style of load depends on the weight of the pistol, the powder type used and maybe the type of recoil spring in the weapon as well as
the ability of the shooter.

Shooting a 38 oz. 3.5" is a lot different than a 21 oz. 3" pistol with the same load.

A full +P load in a 3" Kahr, fired out of my C9 3.5" pistol feel like a standard factor load and a target load out of my heavy 5" Milt. spec weapon.

I beleive this is why there are so many fluxuations in a 115gr FMJ by all the companies.
The different fps, lets you pick a box of ammo that feels right in your certain weapon........
since most of use don't want to shoot Underwood ammo all day long.