What Drew said is pretty much right on...I'll add that the 17hmr has several bullet choices to choose from...the better chuck ammo would be the 17gr TNT/Speer hollow points and even better the 20gr Hornady XTP or CCI Gamepoint rounds, they're designed to penetrate in heavier critters instead of fragmenting on like the Vmax. Chest or head shots will work fine on them, although chucks are known to make it too their holes with marginal boiler room hits.
As far as I know, all H&R butt stocks will fit any SB1 or SB2 frame with the exception of the forends which might require some barrel channel change to fit the heavy barrels. I've switched several synthetic and wood stocks around between centerfire, shotgun and rimfire frames, they all fit so far.
$109 is a great price for a Sportster any place but at Walmart where their retail price is $104.