So I know you can have a integral suppressor on an air rifle without worry but I assume you cant build one and install it as it would be construed as constructive intent if you own other firearms. You would have to buy a air gun with the suppressor as a factory part. My thought is I am buying a nice RWS .22 air gun and I have several .22 suppressors. It probably would not be a big deal to thread the barrel and then I could plink around my house without irritating the neighbors. The cans are factory built NFA items so what they go on should not matter but it got me wondering about building a can specifically for the airgun which technically would not be a NFA item once permanently installed however you could not build it without first getting a form 1 approved and a stamp without being guilty of constructive intent. Isn't that what you would assume? You might have an argument to build a air gun suppressor without a form 1 if you did not and never had owned firearms but once you have a gun building any suppressor would require a stamp. Really it would probably be real risky even then. Just a thought.