There are also huge differences in the terminal effectiveness of the hyper velocity rounds. There are the ultralight frangible rounds like the CCI stingers that will barely penetrate a few inches of flesh, but will expand violently and do significantly more damage on small game compared to more standard rounds. Then there are the fast, solid 40gr rounds like the Aguila Interceptors that will easily penetrate probably 20-24 inches of gel from a rifle and probably 16-18" from a 3.5" pistol barrel. From a rifle, the 40gr CCI velocitors seem to actually be able to expand to decent diameters (.33" in the brassfetcher.com tests), yet still penetrate to acceptable depths (12-13" or so, it seems).
I keep the P22 loaded with Interceptors for the GF. It's still a .22, but it's the only handgun she has ever enjoyed shooting, and at least it will penetrate well with those loads. The Interceptors are available in 500rd bricks for about $50 ( AMM-065 - Ammo .22 Long Rifle Aquila Interceptor Copper Plated 40 Grain 1470 fps 500 Round Brick ).