As long as the bullet will pass without striking a baffle or blowing up due to excess pressure, any suppressor will reduce the sound. How much suppression you get may be less than it could be if the can were designed for that round.
Some years ago a couple of guys in the neighbor town was caught for illegal hunting. They used a 223 with a 30cal can, later when their equipment was for sale at a lokal gunshop I bought the can. (In Norway we don't need to apply for a NFAform or like it, it's a free item to purchase) Our weapons have to be registred, but cans are free.
Anyway I know these guys loaded their own ammo to get it subsonic and they was doing it for years before they got caught.
So to silence a gun it is important to have the right ammo.
I have a YHM Stainless 5.56/.223 QD (Quick Detach) suppressor. It works great on my .22's including the walther p22 on that it is so quiet even with super sonic rounds (i guess because the barrel is so short). Anyway, YHM says if it gets lead build up from .22s, just fire some .223's through it and it will clean it right out. P.S. some suppressor manufacturers have had posted not to use their .223 suppressor on a .22. You might want to check with the manufacturer of the suppressor you have or are thinking of getting.
.223/ 5.56 suppressor on a .22 works great. I have a stainless steel YHM Phantom QD (quick detatch mount) rated for full auto fire. I use it on a walther p22, and also on a Sig Mosquito, also a Ruger 10/22. It is super quiet with subsonics, and even standard rounds at 1200 fps out of the pistols, I can't tell the difference in sound with the suppressor on them;
Info from YHM - Yankee Hill Machine, to clean it out after shooting .22's just fire a 5.56/.223 through it. Mine has stayed clean with no build up. I also give it a squirt of remington spray oil with teflon in it which may help keep anything from sticking.
Last edited by Drsteagle8; 01-15-2010 at 09:28 PM.
Reason: I had already posted this, and somehow missed it so I reposted. Remove?
To the original poster, I notice you mentioned the Walther .22. I would highly suggest you buy a quality name aluminum .22 lr can that can be pulled apart for cleaning. The 5.56X45 can will be too heavy to cycle on a pistol. My cousin has a Gemtech .22 can that he uses on his Walther and he had his kid's .22 lr Cricket bolt gun threaded for use with the can. So you can get double duty with the Walther and a .22 rifle.
As I would suggest to anyone considering the purchase of a can, especially a 5.56X45 can, actually demo one yourself. Internet opinion and "you tube" video are not going to be your actual experience. Unless you have a modern .22 can that you can use to copy, which has it's own issues, it will be hard for you, the first time out, to get a light efficient .22 lr can. The big names have spent quite a bit on R&D to have the designs that they currently have. You can file a Form 1 and make a can. The big question to me would be, would you really be happy with it?
There is also a legal issue to consider. The BATF&E considers internal suppressor parts to be a suppressor, in and of themselves. You can NOT have any spare parts. If a baffle doesn't turn out right, it will need to be destroyed. Is the "Black helicopter" guys going to be watching you? No. But a spare baffle "could" in the right set of circumstances, make you spend what you would pay for a transferable Colt M16 A2 on a lawyer in Federal Court to keep you out of prison. To me, even if I could do the work, the can probably won't be as quiet or as easy to use as a quality maker can.
If you are interested in a 5.56 can, I would highly suggest you demo it. To my knowledge, no manufacturer that I know of makes 5.56X45 subsonic ammo that will cycle a semi/full automatic firearm. To make the semi/full auto work supersonic ammo must be used. While muzzle sound signature masking has a tactical advantage, as a collector, that has not been an issue for me. I have been in the presence of and demoed 5.56 cans. To me, with supersonic ammo, they are too loud. Some might disagree. That is why I highly suggest that you actually demo a 5.56 can before buying or at least transferring to you. Good luck with your .22 lr/5.56 can project.