“[The] .45 ACP shotshells are really a fun round. Essentially a mini shotgun shell for your 45 ACP Semi-Auto handgun. 45 ACP shotshells can be formed from various source cartridges but, 308 Winchester is a good choice. 30-06 would work but should be avoided due to the potential for extractor breakage on the thin groove.”
This is a neat little trick if you have .308-family brass that you can’t use anymore for whatever reason. Good load for pest control and small game-hunting. Also would be fun for busting hand-tossed clays.
Definitely not a self-defense load and there’s no such thing as “warning shots.”
Here’s where The Ammo Channel found the loading data. Not surprisingly, the hand-loaded shotshells outperformed all the tested commercial shells. The die information can be found at RCBS. There’s a short write-up here.