I was really impressed with the .327 Speer 100g GDHP in a recent gel test I conducted.
I shot through 4 layers of denim, 16" of 10% clear ballistics gel, and finally a catch box with packed corrugated cardboard.
I fired a series through my Single Seven Birdshead with a 3.75 " barrel, and then repeated the XTP only through my Single Six 5.5" hoping for improved results. All the shots penetrated a similar amount, 16" of gel and 2-3 layers of cardboard, except the Federal.
Federal 85gr Hydra-Shok was an ice-pick. It penetrated 16" of gel and 50 layers of cardboard. It did not expand (.312").
Hornady 100gr XTP reloads expanded to .36" with the 3.75" barrel, and .41" with the 5.5" barrel.
Speer 100gr GDHP factory and reloads were similar to each other, with the reloads expanding slightly more. Minimum expansion was .48". Unfortunately, it appears they no longer make the reloading bullets, just factory ammo, and that is scarce. Fortunately, I have enough for defensive purposes and a lot of XTP and cast bullets for general shooting.
The XTP might be nice in a theoretical lever gun (XTP in my 9mm AR does great). The Federal is going to get used up for plinking, which is surprising because the Federal Punch 120 gr JHP .38 Special+P did awesome with my Model 15: .51" expansion and 14.9" of gel.