I'm new to suppressed pistols and have a question.  Can a .40 caliber suppressor be used on a 9mm and even a .22 caliber pistol?  Is the sound suppression degraded significantly by shooting an undersized round out of a larger caliber suppressor?   Thanks for bringing me up to speed on this.

To awnsera couple of your questions
Yes it will shoot 9mm
Unless its serviceable I wouldn't shoot 22, due to lead build up
No it's not degraded significantly but you do loose some suppression
Personally I bought a .45 osprey even though at the time I didn't own a .45

I've got an AAC Evo .40. I plan to use it on my 9mm also.

yes...it will be slightly less efficient than a dedicated can for the intended caliber, but most everybody here does just what you mention...at least until they buy more suppressors. :D

it'd be fine on the 9mm, but most will say not to use it for 22LR, especially if the can is not servicable

the best recommendation, unless you're ready to jump in an buy a bunch of cans, is to buy a .45 pistol suppressor...so you can shoot .45, .40 and 9mm.  That's what I did for my first pistol can and I don't even own a .45 at this time.  Added a 22 can to the mix as well.

Same theory as buying a .30 cal rifle can to use for .308, 300BLK, 6.8mm and 5.56/.223.

Thanks for confirming what I thought.

How do you like the osprey? I was thinking about one.

Buy a take-down .45 can for your multicaliber needs.

Anything else and you'll have buyers remorse.

~WTS

You can use a .40 caliber suppressor with 9mm. However, as others have said, go with a .45 suppressor so that you can shoot .45, .40 and 9mm.

.22LR is pretty dirty and I'm not even sure I'd recommend shooting it in a take-apart suppressor like the Octane. Even though you can clean the baffles, the birdcage doesn't come out and I can see fouling getting in the area where the piston seats - making it difficult to get pistons back in after extended .22 shooting.

A dedicated .22 rimfire can would be much better.

AAC Ti-Rant .45 is the way to go. I haven't fired any .40 or even 9mm through mine, but I have put a few rounds of .22 LR through it. It's serviceable so cleaning it isn't a big deal.