whoever sells you the can will set you right on the paperwork. Amazon sells books on how to make your own, for 223, .22lr, .45 autopistols. I"ve seen ads for .22lr cans for like $200 or less. Here's a forum about cans
http://www.silencertalk.com/forum/index.php
https://www.amazon.com/s?k=how+to+make+a+silencer+for+a+.45&i=stripbooks&ref=nb_sb_noss
https://www.amazon.com/s?k=how+to+make+a+silencer+for+a+.22&i=stripbooks&ref=nb_sb_noss

here's the amazon ads. I have no idea why the 223 book is so expensive. Paladin went out of biz and anyone can reprint or just copy and sell it? There's less material in it than the 22lr book, for sure. The author tells you to get the .22 book first, cause he explains stuff in that one that he doesn't cover in the centerfire books.