Thirdpower at Days of Our Trailers blog has the results of expansion testing with Hornady Critical Defense ammunition. His uncle tested .45 Colt LEVERevolution, .45 ACP, .40 S&W, .38 Special, and 9mm by shooting them into water jugs and then recovering the slugs. They look like they had uniform expansion as well as good weight retention when compared to the unfired cartridge.
|From Days Of Our Trailers|
This is the ammo I carry in my Ruger LCR in 110 grain .38 Special +P. I like it even more now that I’ve seen the results of this test.