asuming jeremy did do it where does he hide the gun so that nobody else will find it.
Since no one else used the gun but him and thus no one would go looking for it- the possibilities are limitless. Here are some possibilities- removed the scope, loaded it and left it:
1) in the closet it was normally stored in
2) in the bathroom near the other guns
3) under the pallet near the bathroom window
4) in one of the outbuildings
5) in his trunk and contrary to popular belief he drove to WHF with it in his car
This is just some of the possibilities. Where he would not leave it is out in the open somewhere people would see it and touch it because they would be highly likely to move it and might put it somewhere he could not find it.
Logic suggests he would prefer leaving it someplace he could access it right away while going through the bathroom window thus an out building or the bathroom as opposed to behind/under a couch or the like but some people hide things more than they need to.