A few months ago, someone posted on this forum that he liked the Big Sky racks sold by Cabela's and posted some pics. I looked them up, saw the good reviews and bought one for myself. They sell both a single and double gun rack ($100 & and $120, respectively). It mounts by clamping around the roll bar. I have a P2. Doesn't interfere with the side doors, if you have them on. Be sure to get the one specific to UTV's. They sell a similar rack which screws into the metal posts (like inside a truck cab). Just make sure you are looking at the UTV model when ordering.
Use this link to look at them: Big Sky Racks UTV Bar : Cabela's
I like the fact that they are up over head--completely out of sight from outside, with the hard top. Away from blowing rain and most splashes, too. Good steel, adjustable width, precision fit, and took less than 20 minutes to install myself--no drilling.
I had considered the place at the rear where Butch mounted his rack, but I had the Honda gear pouches running full width of the rear roll bar just below that. Afraid it would be in the way of a rack. Then, I found this model. You only lose a couple of inches of head room. Even with a helmet on, anyone shorter than Jabar will have no issues.
I haven't tried to adjust it for a hand gun, but any long gun--with or without a scope is easy to mount. This may sound like a Cabela's or Big Sky commercial. I've always been pleased with Cabela's--sometimes pricey, but always good quality. I have some of their bibs and a riding jacket in which I've never been cold. Never tried Big Sky before now, but pleased so far.