1st post intro & design/machining ideas & questions

Yes, it can be legal to make a silencer. For everything Form-1, from silencer designs that are easily made, to filing forms with the BATF, to 3D modeling. Remember, you must have an approved BATF Form-1 to make a silencer. All NFA laws apply.

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1st post intro & design/machining ideas & questions

Post by Quietiskept » Mon Sep 21, 2020 1:39 am


I’ve been enjoying reading here. I’m into fabrication, welding, engine building, and just started getting into some home machine shop stuff- small mill and old but tight atlas 12x36 lathe.

So I’m waiting on my 1st form 1 to go through- of course I’m not making anything until I get approved and get a tax stamp from the alphabet boys (hi boys!)

I put 6” 9mm can in my application so as far as I know those are the restrictions I will be working with when/if approved. The plan is to make something that can go on some fixed barrel 22lr hosts, maybe .30, and definitely 9mm- possibly with an added external booster later.

I handload so subsonics are no problem in any caliber (maybe a short barrel 22lr some day for cheap rimfire subs too)

I have figured out some things about design from lurking, reading, and looking at lots of cans. I have some ideas to try and I’m confident I can make something that will at least be fun! But I have some questions. Please be easy on me I never made anything like this before.

-Is there any benifit to using some kind of thread diameter I can find in a book? I think I would do ok to clean up the tube and just cut propriety threads, then match them with a custom thread on the caps?

-Dunno how fancy I’ll get but it seems the hot ticket is to relieve the thread minor diameter a little so the dirty baffles can slide by the threads, and maybe dogbone the can a little for weight?

-If I get around to making a booster to run tilting barrel pistols the commercial Neilsen devices all seem pretty similar- piston and spring occupy ID to insure alignment, spring in the 20lb neighborhood. But all the pistons are heavily scalloped on the pressure face. There is so much to think about between how much pressure the piston sees and how much force it applies and for how long. I’m guessing it just needs to disconnect the can long enough to get some momentum into the barrel without slamming it. If it was that sensitive the commercial designs for different calibers would look very different? It would be pretty easy to just buy a commercial spring and piston and turn a housing for an external booster I guess.

Last question or set of misconceptions to critique- for a 6” long can to run mostly on fixed barrels shooting 9mm or smaller subsonics I’m thinking 60° cones possibly symmetrically clipped, small volume first chamber for less 1st round pop. No venting or drains along the outer edges of the baffles necessary for low power subsonic stuff right? I want to go simple but a little fancier than a washer or freeze plug build- the whole point is to have fun doing some machining and have some fun when I’m at the gun club.

Sorry for writing a novel but it does seem like a smart crowd here. If you read this far- thanks! And if you have any comments I’d love to hear them. No hurry I hear a month is normal but I didn’t even send prints yet so who knows how long my stamp will take. It’s all just theory and fun learning about practical physics and metal shaping.

Oh and I almost couldn’t believe nobody had the handle I picked! Haha

-Quiet is Kept

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