I've been fiddling with suppressors at a fairly high level for about ten years now. There is a definite learning curve involved in their acquisition setup and use. Here are a few of the lessons I've learned that you won't find in any of the articles in the prostitute gun press:
1. Most suppressors are overpriced for what they are. We pause now for Howls of outrage from the peanut gallery.
Ok, moving on . . .
2. There are several levels of suppression ranging from mere moderation to "enough" to "overkill". Overkill is what most people are trained by movies and tv to expect. Overkill is possible only with either excessively large or expensive cans and exactly the right ammuntion.
3. Do not place blind faith in Db readings as listed in prostitute gun press articles. Db readings can be cooked. Even if accurate, Db meters do NOT react to suppessor noise exactly like the human hearing does! You have to listen to the suppressor in actual use to determine what it will actually do. There is no evaluation tool like the Mark 1 Mod 0 human ear.
4. Ammunition selection is as important as suppressor selection. There are many subtleties to this end of the equation - enough to make it a pretty lengthy post of its own.
5. The size of the bore of the suppressor doesn't really mean much as to actual suppression. Baffle design and internal volume mean a LOT more. i.e. A good 9mm pistol suppressor will work just fine on .22.
This, by the way, is the Dirty Little Secret of the suppressor industry.
6. .22lr is very easy to suppress to a reasonable level. After that it get "interesting".
.22lr ammuntion is unbelievably dirty. You REALLY want your .22lr suppressor to be able to be disassembled to be cleaned.
7. To get decent suppression out of any centerfire can 9mm or greater in a reasonable size and weight, you will need to go to a wet can (a/k/a "artificial environment suppressor")
8. To get reliable function with a centerfire pistol suppressor with a wide range of pistols, will require a recoil booster (a/k/a "Nilssen device")
9. The larger the round or platform to be suppressed the greater the other considerations in the tactical envelope. Weight, balance, function, POI shift, etc. Since these factors vary from package to package, it is difficult to make general recommendations.
10. Tactially, the solidest, most simple use of centerfilre suppressors is to dedicate a weapon to it and leave the can in place all the time. Any other stratagy may offer the illusion of flexibility but at the cost of tactical effectiveness and robustness.
There is a LOT more to know about cans and their employment. The above are just the thoughts that come first to mind on the subject. I didn't even attempt to begin to address centerfire rifle suppresson -that is more difficult and intricate above rimfire and centerfire pistol calibers by an order of magnitude.
Bottom line: If it were me, knowing what I know now, for an undisclosed 9mm pistol and a .22lr rifle or pistol, I would buy a .45cal AWC Nexus III suppressor and have a thread adapter made to go from 1/2x28 (usual 9mm and 22lr barrel thread these days) to the Nexus thread. That would give you the capability to use the can plausibly on almost any centerfire pistol platform up to .45 and most any .22lr platform.
Your mission requirements may vary of course and may require more specific logistics. Drop me a line if you wish to discuss your situation at greater length. If you feel like whipping up here to Oregon for a weekend I can walk you thru the entire schmeer from .22lr to centerfire pistol to SMG (integral and snap-on) to centerfire rifle (integral and snap-on and tactical CQB moderators).
I stole this from elsewhere... Discuss section in bold please