So who makes factory bolt guns with threaded muzzles? I know Savage has one of their higher end models that is threaded but I'm not sure if anyone else does. I would like to have a lefty to shoot suppressed, preferably without having to pay to have it threaded or doing a Frankenstein barrel swap.

Ruger has a lefty scout rifle that has a threaded on flash hider.

I screwed a Silencerco Harvester onto my .308 Scout with a 5/8-24 adaptor and it worked fine.