It’s possible IRL, so it should be possible in game, right? As long as you are wearing pants, you should be able to put a gun in your waistband. Maybe have some minor encumbrance penalty.
I’m okay with it, if the following conditions are met:
-if you run, it will spontaneously drop on ground
-if you use any move from any martial art style, it will spontaneously drop on ground
-if you try climbing up/down spigots or ladders, it will spontaneously drop on ground
-if you do anything requiring at least a modest level of exercise, it will spontaneously drop on ground
-if you are suddenly hurt or at high pain threshold, it will spontaneously drop on ground
-if something else happens, well, I think you get what I’m getting at
On a slightly related note, holsters are an oddly rare drop for a game world with ~6 bazillion guns in it. I mean, you can find all kinds of ankle holsters, back holsters, concealed holsters - but a good old fashioned hip holster, the one you need to fashion harnesses and stuff from? GL/w that.
Oh, and its crafting recipe is also rare.
You can “hack” them in now using the Bionics mechanics. Couple years ago, I made a character who started with an arm crossbow (Monster Hunter’s Slinger except inspired by something else).
That makes no logical sense. Unless your pants are 10 sizes too big, a gun will stay in your waistband pretty securely. Otherwise you’d see a lot of guns on the sidewalk.