There is a guy on Varminter.com who wrote a book (steve b) on rimfire ammo the 20 gr made a very good wound channel. other there like is on gound hogs but it seem to need to hit bone to really do damage.
I shot a procupine with that load and it was DRT and did not even twitch.
I am not sure if I would use the 17 gr tnt or the xtp part of me wonders how the xtp would perform on a straight rib shot would it expand enough. Where as the 17 tnt will expand but give more penetration than the v-max.
I would have loved the hmr years back when I hunted foxes more, I have ony seen 3 since moving to AB.