My Omega 9k from Radian Weapon's Black Friday Sale finally arrived last month and I have it pending. I plan on using it on an UZI carbine SBR and 9mm handguns, primarily. I went about ordering some adapters in anticipation, here's what I got:

I'll have the 1/2x28 adapter and piston, 13/5x1LH piston, and the 5/8x24 adapter.

For 9mm handguns and PCC is there any other piston or adapter I'll need? Might as well get them in advance.

I'll be picking up a low-pro 3-lug adapter soon.

you should be covered for 9mm semi-auto pistol with a few exceptions

PCC is going to depend on caliber, if it's 9mm then 1/2x28 fixed adapter should do it

5/8x24 should be good for 308 and 338

FYI, the low-pro 3-lug mount sacrifices blast chamber volume and is considerably louder than the longer 3-lug mount.

If you can possibly stear away from anything with LH threads it would save a lot of aggravation. I don't know about Omega but all my cans have RH threads. Tightening one loosens the other. I have an HK 45 that came with LH threaded barrel. Only can that requires blue loctite.