Man I wish my walmart had 17 hmr ammo...
About a year ago maybe less I even asked to speak to the lady responsible for ordering ammo and she told me was not going to happen as soon as I said 17 hmr... not sure why??? too hard to get or something she said.
My gun prefers 17gr but I have and use both it and the 20gr. I have tired cci, fed v-shok, and hornady in my gun, a savage.
I too have noticed while the 17gr does kill, I've had small critters crawl around after being shot with it. I was very surprised too considering the amount damage the critters receive from the round. Huge wounds, tons of tissue damage.
Even if I believe the 20 gr has more stopping power or penetration I still doubt I would shoot a fox with the 17hmr at all, regardless of bullet grain... I'm sure some will disagree with me but in my fox hunting experience anything less then a head shot even with 22 LR requires chasing and searching for them, the last fox I shot I used a federal 50 grain 22mag and he was anchored on the spot with a shot thru the vitals. I was much happier with the results even compared to the 22LR. I don't have gophers here, so my 17 is mostly used on paper and the odd furry or feathered pest that moves into the house or garage.