so how did it shoot these are on sale at cdnn for 229
I was under the impression that silencers were illegal. What's the law to have one? Must it be of 22 cal? Can someone elaborate?
Not illegal at all, just requires additional paperwork, background checks, and a $200 tax or fine depending how you describe it. Here are a few links with more information that should answer most of your questions.
https://www.indianagunowners.com/forums/class_iii_nfa/20357-nfa_myths.html
https://www.indianagunowners.com/forums/class_iii_nfa/6459-nfa_faq_s.html
https://www.indianagunowners.com/forums/class_iii_nfa/26144-nfa_from_a_beginner_s_perspective.html