Stephen Camp has an article on the FBI load on his website,
www.hipowersandhandguns.net. In his informal testing (soaked newsprint), he concluded that, from a snubby, Federal and Winchester 158gr LSWCHPs probably would not expand -- too hard an alloy. However, the Remington version, with very soft lead bullets, probably would expand when fired from a snubby. For more formal testing, check
www.brassfetcher.com. Their ballistic jelatin test of the Remington, fired from a snubby, was very impressive. From longer barrels, the Winchester and Federal bullets should expand, but from snubbies they just don't have enough get up and go.
Cordially, Jack