Looking to get 4 cans. My thoughts are the following:
5.56 surefire RC2
308 AAC 7.62 sdn6
22 silencer co sparrow
9 silencer co octane 9/dead air Odessa 9

What do you guys think? Any suggestions welcome

Better .22 options are Rugged Oculus or DA Mask.

For 9mm, are you looking for pistol, PCC, or both? Rugged Obsidian 9 or 45 is a good all around can.

Not sure I’d go AAC for a can right now since they just changed ownership. Personally, I prefer the DA Nomad 30 for a rifle can.

The YHM cans are also worth looking at.

Of course in all this like many things in life there are a zillion tradeoffs in design of suppressors. So it matters a little (and sometimes a lot) exactly what you are doing with it, what properties are important to you and what are you shooting out of it.
That said...
the surefire is a good all around choice, though a bit pricey. its my personal choice and no complaints.
I would never buy an AAC product at this point.
The .22cans I'm with Dwill104 the DA Mask and the Rugged Oculus are probably better and I have no complaints with either at a personal level.
on 9mm I'm a fan of the DA wolfman and the Obsidian 9 but can't really comment on your choices from any actual knowledge.

I think you are on the right path to suppressors. A caliber specific approach makes sense. I'm going to make a few suggestions.
1) Decide on a Standard mount for 5.56/7.62. Current industry standard is a 1.375-24 aka alpha , omega or H.U.B.
This allows you to use your 7.62 can on a 5.56.
2) Weight and sound reduction of the suppressor. You will get many recommendations for which suppressor to purchase. Rifle cans need to to made of stronger materials than pistol cans , translates into a heavier can. K baffles tend to do better than monocore for pistol (rimfire) cans.
3) Subsonic always will suppress better than supersonic. The most effective calibers for suppression are 300 BO and 22 LR. 45 caliber is typically subsonic. 9 mm needs the 147 bullet weight to be subsonic.
4) Rimfire is dirty and a pain in the ass to clean. Titanium or stainless steel baffles should be the 1st choice.

7.62 can-- Energetic Armament Lux.
Rimfire-- Deadair Mask, Energetic Armament Nyx
9 mm--CGS Mod 9. CGS and Zev teamed up to make the Kracken --the 1st gen version of Mod 9.

Having 1.375x24 rear threading on a can is mainly used for screwing in adapters that allow the use of other companies muzzle devices with your can. For example, a mount adapter that allows the use of Griffin taper mount muzzle devices with Dead Air or YHM cans. What allows the use of 7.62 cans on 5.56 is having muzzle devices to attach the can in the proper thread pitches, which almost every manufacturer does. An example is a DA KeyMo muzzle device, which is available in multiple barrel thread sizes. Even in cases of a direct thread cans with a removable rear end, the company will make different barrel thread adapter to fit their own can, even if they use a proprietary thread pitch.

I agree that the 1.375x24 cans deserve a look, if versatility is a top priority. One thing I have appreciated over the years is A2 or NATO mountability, which comes with the 1.375 anyway. Just get something, and start shooting with it. Your opinions and preferences will likely evolve, and you'll get another can down the line anyway. Don't spend too much time assessing everything.

I went with Surefire SOCOM mounts and 5.56 and 7.62 RC2 cans. The paperwork is sent off and they are in jail for the next few months.

Going with the standard military mount, which is available in many threads makes sense. It's not getting orphaned any time soon. The RC2 cans a lower backpressure with minimal POI change. They are not the lightest or the quietest, but they are more or less indestructible, with all inconel baffles, MG rating, etc.

The 7.62 RC2 will work with 300BLK but it's not the best option. My only 300BLK is a Rattler so I might end up with a dedicated direct thread taper mount can for it - Sig or Q maybe.

Handguns I haven't worked out yet. I'd like a Tri-lug option for the PCC's and need 1/2-28 and 13.5 LH for 9mm pistols. Also need to settle on a .22LR can.

The only issue I have with the RC2 556 mounts is their availability. Surefire has much trouble keeping up with the demand for their SF3P mounts. The sell at MSRP within minutes on almost every site they're listed on.

I did essential what the OP asked about, except my pistol can is for both 9mm and .45ACP guns. I bought a Rugged Obsidian 45 (comes with a piston for .45) but ordered an extra 1/2x28 piston and a 9mm end cap for it. I just picked it up from the dealer last week and haven't had a chance to shoot it yet. Maybe tomorrow.

My other cans are a DA Mask for .22, a YHM Resonator for .30 (and 6.5CM) and a YHM Turbo T2 for 5.56. The resonator works great on a 5.56 rifle too. No regrets with any of them.

I bought a 9mm endcap when I bought my Obsidian 45, but never used it. Too big a risk of leaving the smaller endcap on by mistake and getting a strike. The small improvement with using the 9mm endcap on a 9mm gun wasn’t worth the risk for me.

Worth the risk? You make it sound as though forgetting to swap back to the .45 endcap would actually damage the silencer itself. You'd look a little silly, and be out what you spent on the 9mm endcap, but then you could just shelve your factory .45 endcap, and use your "custom" one!

Or am I missing something? Is it built such that it could potentially "rip" the endcap out of the can, thereby actually damaging the body?

and as a practical matter all the data I have seen shows that an endcap change doesn't buy you very much in any case.

quote:

Originally posted by KSGM:
Worth the risk? You make it sound as though forgetting to swap back to the .45 endcap would actually damage the silencer itself. You'd look a little silly, and be out what you spent on the 9mm endcap, but then you could just shelve your factory .45 endcap, and use your "custom" one!

Or am I missing something? Is it built such that it could potentially "rip" the endcap out of the can, thereby actually damaging the body?

I don’t necessarily think it will damage the tube itself. You’re reading into my comment what isn’t there. I’m simply not interested in damaging an endcap, whether or not I have a replacement available. Once an endcap is damaged, I won’t use it again, so it’s just wasted money. Plus, it only makes a minor difference from everything I’ve read.

It’s not worth it for me. You do you.