Little bullet in big can

[chuckstur]

Any experience in how much efficiency is lost when shooting a caliber smaller than that for which the suppressor was designed?  e.g. .22 in .30 cal can, .30 cal in 9mm can, etc.

[Slappy]

Lots of variables involved so it's hard to give a straight answer. Such as, bullet weight/speed, barrel length, type of can, length and girth if said can, size of end cap on can. Generally speaking, you will lose some sound suppression but probably not as much as you'd think because the increased volume of the can helps make up for what you will lose shooting a smaller bullet. 

[Jct1911]

Given that one can is the same size. The tighter bore is more efficient at stripping gasses. But most cans are caliber specific, size wise and bore wise. 223 usually is more quiet in 30 caliber sized cans. 22lr really quiet but usually has a tad more first round pop.