A member of the team I play with, runs a pistol only. He just hides in a bush and waits for people to walk past and shoot them or in corners of buildings with the pistol pointed at the door ?
Out doors done a couple games with just a mk23 nbb and switch to a pistol if temperature allows for base clearance. CQB generally play with a GBB pistol/SMG.
I'm thinking of extending my pistol collection. I very nearly bought the 4" Dan wesson revolver (prefer the 2.5" but couldn't find one in the right colour) but bottled it last minute for fear of never using it and the fact I need a new slide for my 4.3 Hi Capa!
I'd check with your local site as well, as some places frown on them because of the ease of slipping full power shells back in and point-blanking folk with them.
I know, I know, there are plenty of other ways of cheating chrono, Y U NO MED Mk23s, and so on, I'm just flagging it up.
It's easy to mod the standard shells to x3 shot and still be a skirmishable even if you had the 4" barrel. The shells can take up to x6 with a bit more work but I had to mod the gun to output more gas to push x6 bbs with a 2.5" barrel, not sure how 4"would go. It also has a hop unlike many co2 revolvers. Shoots x6 out 20m or so with about a 3ft spread at 10m. I prefer it to carrying a breacher.
Ive done this once when my new AEG was chronoing too hot. Ran with a WE TT-33 all day and I genuinly had one of the best days of airsoft i've ever had.