Ok so...
The broom must be enchanted or a spell must be used such that the head/bristles deform out of the way or into an accomodating shape for the shooter, or at least be removable, otherwise the buttstock is non functional, and shouldering/aiming the rifle would be extremely troublesome.
Also if this is the kind of broom you ride for transit, you're going to be sitting right on the bolt/ejection port/rear sight (the name suggests its basically an M1 Garand with chibi proportions)... so you'd need some kind of spell or enchantment to handle that, or some kind of saddle, or lower body wear with a reinforced crotch, not the drawn rolled up pants/shorts.
It would at least work as a broom.
That can potentially blow your head off while using it as a broom.
Or perhaps the entire thing is a non functional artefact of some kind?
Edit: Also not sure about the practicality of an ammo bandolier around a hat with a wide brim, though I guess the hat could also be enchanted such that it deforms out of the way to make reaching for ammo easier...