[Cushman]

This is a good point, but as my sibling points out there are suppressors and there are suppressors. It's certainly well in the ability of a competent amateur to make an effective suppressor for .22LR -- I understand you can use PVC or such materials -- but try that with a larger caliber and it'll take your finger off with a decidedly non-silent noise.

You're going to need a lathe, at least -- a machine shop would be better. Even if you copy an existing design (the science is mostly understood, but it's still easier to make one that doesn't work than one that does), the metallurgy is important-- you really need someone who knows what they're doing.

And that person had better hope that no one outside of the crew knows that they know what they're doing, because as soon as those off-brand suppressors start showing up on the streets, finding that person will become the number one priority for a number of very highly trained forensic experts. They really do take this stuff very seriously.