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Form 1 suppressor build
bkoenig:
OK, here we go. For anyone who's not familiar with this process, it is legal to build your own suppressors. The legal requirements are identical to building a short barreled rifle (SBR) or short barreled shotgun (SBS). You fill out ATF Form 1 and pay a one time tax of $200 to Uncle Sam, and send it all off the the ATF. After a LONG wait (mine took 6 months) if everything is in order you will receive your form back with a tax stamp. Once you have the stamp in hand you can legally begin construction. Building any part of the suppressor, even a single baffle or threading a tube, before that time is illegal and will land you in the graybar hotel if you get caught. $200 is a pretty cheap price to avoid having a really friendly guy named Bubba as your room mate. Don't be stupid.
I will be building a .22LR suppressor. It will be built out of 6061 Aluminum, except for the first baffle and the barrel threads which will be 303 Stainless for durability. Aluminum is fine for a rimfire suppressor, but is not strong enough for centerfire. The baffles will be what is known as a "K" baffle, because when they are viewed from the side they look like two K's back to back. This baffle type generally works well for subsonic and low pressure loads, but it is a little more complicated to machine.
Quick disclaimer: I am not a professional machinist. In fact, I'm not even a particularly good hobby machinist. I will most likely make mistakes in this build. Build a suppressor can be dangerous, both from running machine tools and from using the suppressor itself if it's not properly constructed. Don't attempt this without a full knowledge of the risks involved. I'm not responsible for your safety.
With that out of the way, let's start turning metal. I turned down a bar of aluminum to 1.027", which makes for a slip fit inside the tube. I don't want it too tight, as rimfire ammo is very dirty and this will need to be disassembled frequently to clean it out. The bar has been drilled with a .25" drill bit. I may make the final bore slightly bigger, depending on how my tolerances stack up.
6061 machines beautifully. A sharp bit finishes it to a mirror finish. Also, the chips are extremely sharp. I have a sore index finger to prove it.
bkoenig:
Next steps - cutting the front "disk" of the baffle. Since I already had the bar chucked up between centers I just left it there for the first one. This was a mistake since I had to then part it off and rechuck it to hollow out the inside of the cone. The next one I'll be smarter.
bkoenig:
Cutting the outside of the cone. The compound is set at 30 degrees to create a 60 degree cone. I didn't get any pics while I was machining the inside, but this is where I was dumb and had to part it off and rechuck it.
bkoenig:
And here's the (almost) finished baffle. I still need to plunge a 1/4" ball end mill into the face and from the back to create a "scoop" in the face and a vent in the back cone. This will vent gasses to the outside of the cone. It's a little hard to explain but will make sense when I have pics. 6 more baffles to go.
bk09:
How did you learn to make this before you undertook the project? Did you take apart other suppressors and look at them or did you find blueprints somewhere? If/when I get the tools this would be of interest to me.
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