Kel-Tec

Kel-Tec designs firearms nobody else would attempt, and that is the whole proposition. The KSG holds fourteen shotshells in a bullpup frame; the Sub2000 folds in half and takes Glock magazines.

The engineering is genuinely inventive and the aesthetics are divisive. If you want something conventional, look elsewhere; if you want a solution nobody else is offering, this is usually where it exists.