Undetectable Firearms
They were right under our noses the whole time.

PopPops should be undetectable by firearm and similar detectors, and maybe weapons checks (though thats a whole different discussion). Ammunition does not set of these detectors, and they are made of non-firearm materials as they are disposable outside of that ammunition. It would make PopPops, while not the first choice of weapon, a useful one in certain circumstances or as backup hidden weapons that would be balanced out by their already integrated downside.

Just a thought, let me know what you think.

Always loved the scenes where someone puts together a sniper rifle or rigs a spy pistol out of something. Would add risk too, having to reassemble it once you're past a checkpoint. I can think of a variety of places where this could work well though.

This one's half-baked, but I like it.

Anti-detection gun mod.