60 gr subsonic .22 ammo, .22 SHORT cases

[softpoint]

I built two 22s specifically for that round with 1:8 barrels. No baffle strikes yet, but I did have a dud round make it halfway down the barrel.
The bolt action build is insanely quiet with that ammo and a SiCo warlock. By far the loudest noise is the firing pin hitting the rim.
It’s what I recommend to anyone who has a 22 conversion kit for their AR. Basically, it turns it into a subsonic 223

Oh, the SSS rounds smell bad when fired. Kinda like the elephant exhibit smell.

That bad smell is Eley priming compound. Aquila and several other rimfire ammo makers use Eley priming compound, and it has a unique odor.

[TacticalCowboy]

I had a mark 3 that would feed shorts. Had to alternate between LR and short rounds in the mag because the shorts would nosedive by themselves.