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.
I decided I wanted a can for my new 300 Blackout build so I took my lunch break today at the computer and drew up a down and dirty mono core can. It took about 1/2 hr to draw and post the code for it, 15 min to set up the mill and another 20 min to cut it.
I am pressing it into a stainless tube and welding on the end caps tomorrow.
I know it has a lot of metal that could be removed to add volume but it should work fine with 220 gr subsonics.
If it does not work good enough I will cut it up and spend the time to make a better one.
07/SOT. I pay them $1000 a year, I can make whatever I want.
I have been waiting for almost 3 months on the determination letter from ATF on the 80% 1911 frame as a non firearm item so I can start selling them without worrying that they will come back later and say they are firearms.
jfk wrote:Do you thread before or after you press and weld?
I turned the OD, ID and threads for the mount in one operation then parted it off, faced the other side and pressed it into the tube. I went .001" oversize.
It weight 1 lb 6.8 oz. It seemed a little heavy so I weighed my Surefire .308 can. It weighed 1 lb 7.6 Oz with the mount. The Surefire is a little lighter without the mount but total weight on the rifle is what matters so I weighed it with its mount since my new one has a mount as part of the design.
I just welded it this AM and turned the welds smooth on the lathe. I had to chase the threads in the can because after welding they were tight.
I put it on my new 300 BLK build and shot it behind my shop. It was as quiet as any commercial can I have heard on an AR15 in this caliber. I used Remington 220 grain subsonics.
It is not as quiet as my partners AAC can on his Remington 700 bolt gun in 300 BLK but that is to be expected. I will have to try it on a bolt gun and compare it to that.
The above is not to say that this can works great, just that the 300 AAC Blackout round is an awesome round that is easy to suppress.
I decided I wanted a can for my new 300 Blackout build so I took my lunch break today at the computer and drew up a down and dirty mono core can. It took about 1/2 hr to draw and post the code for it, 15 min to set up the mill and another 20 min to cut it. 
