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'll keep it nice short and quick. Would aluminum be ok for a suppressor in 7.62x39 if it was only used with subsonic ammo? Don't care about ballistics, expansion, etc.. Just a budget popper with cheap 30 cal reloaded 154gr sp ammo. I am "GUESSSING" that the exit pressures wouldn't be too bad, especially when some of that will be used to attempt to cycle the action as well.
What I can tell you is this...I loaded some experimental loads the other day. I had some 7.62x39 training ammo. I pulled it down and re-loaded it with 13.5 grains of AA5744 under some 174 grain SMK .311 diameter bullets. Accuracy was good and there was no evidence of key holing. Velocity was in the low to mid 1200fps range through a Yugo M70 Ak. I experienced no cycling issues and the cases were ejecting 10 or so feet. now for the disclaimer....This info is what I experienced through my firearm and take no responsibility for what you decide to do with it. For the record however Western Powders has published "reduced velocity" load data for this ctg. on their web page. I am planning some more experimentation in the near future
"The Constitution shall never be construed to prevent the people of the United States who are peaceable citizens from keeping their own arms."- Samuel Adams
"LP"
That is certainly interesting info. I guess the real question is how could anyone know what the exit pressure is. That'd be the only determining factor if an AL tube (albeit a thick one)would be able to handle the exit blast. I'm sure it was greatly reduced over a full load though.
rejma0415 wrote:That is certainly interesting info. I guess the real question is how could anyone know what the exit pressure is. That'd be the only determining factor if an AL tube (albeit a thick one)would be able to handle the exit blast. I'm sure it was greatly reduced over a full load though.
In the EU there are several manufacturers that build 38mm diameter silencers from Aluminum tubing and combined steel - aluminum cores for large calibers 30-06 and above, including some of the short magnums.
All intended for full power hunting loads. These are not made for FA use but we all do understand that.
rejma0415 wrote:That is certainly interesting info. I guess the real question is how could anyone know what the exit pressure is. That'd be the only determining factor if an AL tube (albeit a thick one)would be able to handle the exit blast. I'm sure it was greatly reduced over a full load though.
I believe the quickload software has some theoretical data for different pressures....chamber pressure, muzzle pressure, port pressure. and how those pressures relate between loads. I believe barrel length is one of the variables that can be input for calculation. I do not have Quick Load so I cannot confirm nor deny.
As it has been mentioned by MCKNBRD.... AL is not going to get a whole lot of support and while the intent may be to use with subs only....not many could resist the temptation to just let just one mag of f/p loads go through.
"The Constitution shall never be construed to prevent the people of the United States who are peaceable citizens from keeping their own arms."- Samuel Adams
"LP"
Would aluminum be ok for a suppressor in 7.62x39 if it was only used with subsonic ammo? Don't care about ballistics, expansion, etc.. Just a budget popper with cheap 30 cal reloaded 154gr sp ammo. I am "GUESSSING" that the exit pressures wouldn't be too bad, especially when some of that will be used to attempt to cycle the action as well. 
