that is one tiny silencer. the one i have for my PS-90 is twice that size. is there a difference between Semi & full auto slencers in the P-90?

Legality?

No. The civilian version has a much longer barrel than the military version. This is the military version. You could buy a civvie and convert it to military of course, as long as your state/country didn't mind you having a rifle with such a short overall length. Silencer size can vary widely with how good the design is, and how much you want it silenced by.

Rich boy, or airsoft,