Idaho has a weight limit on the gun you can use to hunt with? What idiocy! The way I see it if someone wants to hunt with a 40lb gun let them! Its not my back and shoulder that'll be hurting at the end of the day. Heck I'd bet there's some guys out there with AR rifles that weigh close to 20lbs after all the crap they've bolted on lol!
Wisconsin has no limit on the weight of the gun nor the caliber (well you have to hunt deer with a centerfire cartridge larger than .22 but no max). We also don't have an ammunition capacity limit either when it comes to all hunting aside from waterfowl/migratory birds. I believe that restriction is Federal and not state.
If I wanted to go hunting with a 50BMG that holds 100 rounds and weighs almost 100lbs overall it wouldn't be illegal in WI. I might get more than a few strange looks and maybe a rolling laugh from the local warden but its still not illegal.
Personally I won't be hunting with a .50BMG because I simply just don't want to a) pay for the bugger and the ammo to go in it and b) lug that weight around with me in the woods.
Aside from that I highly doubt it'll cause deer to explode or anything like that when hunting medium to large game. What it WILL do though is most likely kill the target effectively and fairly quickly - so effectively the game may not even know it'd been hit before it dies.
Just a note I DO hunt with a fairly heavy gun - 16lbs with scope and ammo. I use a DPMS LR-308 for my deer hunting. My daughter uses an AR frankengun in .223 although this year I'm going to graduate her to a 6.8SPC. I don't consider either rifle an "assault weapon."
This is who we are, what we do.