Good, old reliable M1 carbine made ugly for the sake of greater utility. Choate folding stock with pistol grip, Magpul AFG (mainly to keep the support hand away from the operating rod), Aimpoint Micro on Ultimak rail. The carbine is held by Lyle Keeney, the designer of Ultimak rails. It’s light enough that one-handed firing is possible.
The same carbine but with a Primary Arms red dot as the more budget-friendly solution.