Hi,
I already have a .30cal suppressor and another inbound along with a 5.56; both YHM. Currently debating on getting a Sig MPX or MCX in 300Blk (still not sure which I'll get) and wonder which can would be best for the 9mm.....if any? I know I can shoot the 300blk with one of the .30cal suppressors (please confirm just to be safe) but unsure if the 5.56 will work on the 9mm. I am going to chop the barrel and have it rethreaded anyway so no worries with that; just not sure about possible baffle strike issues. Thanks!

9mm will certainly not work with a 5.56 suppressor.  9mm is way too big for the bore.

For a 9mm subgun can, look at the Silencerco Omega 9K.

Thanks. I thought as much but wanted to confirm.

In addition to the Omega 9k take a look at Dead Air's Wolf  9SD.  Either would serve you well for 9mm or 300 blk applications.

Thanks. I think I read that re: warranty with the Sig short barrel, Dead Air was the way to go as they don’t specify minimum barrel length. From what I could see, YHM doesn’t either. I’ve two of theirs en route in .30 and 5.56.