I'd say gamers and paintballers, for a few reasons.
Gamers, because most gamers nowadays aren't kids, and most of the combat type games are marketed towards young adults. Also, games now are really action heavy, and have a LOT to do with firearms. Hollywood could learn a thing or two from the videogame industry, in terms of realism. Depending on what type of games you play, you can learn perfect sight picture, a little bit about sniping and leading, and different weapons/platforms/ammunition, etc. all from playing video games... everything but trigger control, really. If you've played video games recently, you know I'm not exaggerating.
I also think paintballers eventually catch on because the very essence of that hobby is basically war-gaming. I'm the only guy I know anymore who's never gone paintballing. Now I always thought this was just a little inexpensive hobby, and I've always wanted to go... until I looked into it. First of all, I could buy a quality pistol (used) for what some of those paintball guns cost. Secondly, some of those guys really know their stuff - I met a couple guys down at school earlier this year who talk about paintball guns like we oooh and aaah over the newest offerings from S&W or Wilson Combat, etc. They talk about lightening their triggers and tweaking their guns just like we do. It's kind of amusing.
And most of them are into guns already anyway. Interesting question, MV. I'm curious to see what kind of answers you get from other folks.
