Talk to me like I'm 10 (supressor questions)

Yes they make 9mm cans rated for 300 blackout subs, they make 9mm cans that run supers too most are IMHO too heavy to hang on a handgun. No you'll need different set ups you'll need a booster for the 1911s tilt barrel to function and no booster for fixed barrel. Most 9mm cans have both methods available.
You say you don't care about weight now, but you will.
The do all cans are like drug dealers free samples and are just a gateway.
I would suggest you factor into the first can a plan for several they are addictive.

I bought a dead air ghost m rated for 300blk subs.
I bought a piston for my usp45.
Then I ordered a fixed mount for my 300 blk.
You either have to use a fixed mount or a fixed barrel spacer with a piston.

Edit
Didn't see the 9mm on the 1911.
But I run my ghost on 9mm .40 .45.
147gr 9mm is really quiet.

The ideal thing would be to have a .22, 45, and 30 cal can.
The 45 could be used on 9, 40, 45, and most likely would be able to handle 300 subs.
30 cal for rifles; 5.56, 308, etc.
.22 for well, .22 rifle or pistol
Mounting suppressors can get expensive. Pistons, muzzle brakes, direct mounts, and fixed barrel spacers get pricey at $60-80 each, and your can doesn't come with them and is useless without them.

There are a lot of cans that come where you can have it long or take a section off to make it short, thereby making it lighter !

Trashyshoots said:

and I know the thread patterns vary for different calibers.

Click to expand...

They don't have to, though.
And, then there's QD, Quick Detach, mounts as well.

If you are buying off-the-shelf cans, then yes, the threading matters. But only to what it will take to thread the host. If the host has a bare barrel, you simply get it threaded to the can you want.
If you want to have more than one host, the other host will need appropriate threading, too. Or, if threaded, perhaps a thread adapter, if there's a difference.

The other issue, with handguns, are the sights. A concentric can is probably going to block your 'native' sight picture (unless you are running an RDS). Now, eccentric cans are availalbe, which preserve the sight line, but will tend to be expensive.

Now, if you buy bespoke, custom, cans, then it's down to you and the cansmith. You tell that worthy, I'd like this to do that on these. That, then gets worked out between you and the smith.
Which will include things like, "If you do what you want now, that will only knock nn dB off" which might not be an optimum you want. Or it may mean a can heavier than you need.

Oh, and fair warning, cans multiply. Just because you currently want just the one to cover more than one host does not mean that you won't wind up with individual ones later.

The problem for a 1911 you need a can with a recoil booster or Neilson device.
Heavy construction big bore silencers typically aren't designed for a recoil booster.
I think your best bet would be to use a 9mm silencer designed for a 9mm. Something like an osprey, where the silencer is off center bored so you can still see and use the sights on the gun.

Also I tried putting my 9mm silencer on my 30 carbine which is pretty much a baby 300 blackout, it did not deliver satisfactory results. It was quieter but still absolutely sounded like a gun shot I assumed it was the gas system making all the noise. Then I got to try out one of those stackable form 1 silencers drilled out for 30 cal with 4 chambers and it was substantially quieter than the 9mm silencer. So I submitted a form 1 to build one for my self, the tax stamp came back now I just got to build it.

Yes, most 9mm suppressors can handle .300 blackout subsonic just fine, and no, you will not generally get good subsonic performance out of a high velocity optimized .30 rifle can unless it's quite large (8.5"-9"+ length). Most .30 rifle cans are built with .308 in mind.

The Rugged Obsidian would be a good one for your needs. They make both 9mm and .45 cal versions. If you expect to ever use a can on a .40 or .45, go with the .45 model, but otherwise, the tighter bore of the 9mm version will work better with .300 blk.