Quote Originally Posted by secretagentmole View Post
Gonads! There is a lot of air exiting the barrel, that is what makes the loud bang noise when you fire the damned gun and why you buy a silencer/moderator/suppressor to begin with.
If you compare the required expansion volume and resultant shock wave of a sub 12/ft/lb rifle to an actual firearm (which account for the vast majority of the worlds 'silencer' requirements) yes, the output is negligible. What i was getting at is that the difference in size between a .22 and a .177 is so small that there is little to no point in building a calibre specific Airgun moderator.

Huggett for example use a 6.53mm aperture so just over 1mm clearance on a .22 and double that on a .177

So far for all the ones I've seen use 6mm+ aperture. I'd love to actually test some built for .177 to directly compare them to the .22 counterparts, but Hugget, Daystate, HW, Hogun etc don't seem to bother with them.
I'm getting the feeling this is rather hijacking the thread form the OPs question.

Bottom line still comes down to the same thing though, for backyard plinking the sound of the action and the pellet impact will be louder than almost any of the standard production units so buyers can pretty much buy whatever they like the look of that suits their wallet.