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.
A few years ago I sent off the paper work for a few form-1 builds I wanted to do. A 5.56 (8") and a 50 BMG (18"). The 5.56 is complete and has worked well for years it was a 8" long 7 cone baffle build with steel and aluminum using threaded endcaps. Over built and heavy but very functional and very effective. After finishing that I ordered the material for a 50 BMG suppressor for an Armalite AR-50.....other projects got in the way and just last week I got started on this build. The rough plan is a steel tube, welded steel endcaps, steel partial cone baffles, and aluminum sleeves to space the baffles.
The more detailed plan is:
A 18" x 3" OD 4130 steel tube with 0.125" wall.
The end caps will be welded on and are made from a 3" 4130 steel bar.
Here is the progress so far with the tube rough cut and the end cap to attach to the barrel cut.
The 8 holes at 0.5" and 0.7" deep (to lighten the end cap and make for interior volume, they face inward and will never be seen once assembled).
The threading is 1"-14.
Next time I work on this project I will start on the blast baffle....but that might be a few weeks from now.
I'm far from an expert in suppressor design, but I'm thinking the aluminum will not last long in a 50BMG can.
What is the wall thickness of the spacers?
The tube itself is going to weigh over 5.7 pounds. Add about 3 pounds of guts and you got one heavy can.
I used 2 inch .065" tubing for my 16" 4.8 pound 50 bmg can.
You can reduce the rear end cap weight further by making it shorter on the outside and leaving about .2 inches for engagement with the tube for welding.
The part in the lower left corner is the rear end cap for a .308 can The threaded part is the only part long enough to engage the barrel threads while the rest of the part is only thick enough to mate with the tube for welding.
3x18 inches will provide lots of volume and make it much less noisy. Good luck.
Ranb
SilencerTalk was a place I could disccuss making registered silencers without being told I was a criminal. That is no longer true. http://www.silencertalk.com/forum/viewtopic.php?f=132&t=99273
This is going on a target rifle that won't be lugged around in the field, so I do appreciate the feed back on weight, but weight is not much of a concern for this build. A few threads I have seen in other places on recoil from 50 BMGs with suppressors vs. with muzzle breaks is that the suppressor needs to weight at least 6 lbs to provide similar recoil reduction as a good break. The target weight for this is between 7 and 8 lbs. I plan to make all the pieces, weight them, and go from there either reducing weight further or welding it together.
The aluminum spacer material is 0.128 wall thickness.
I tend to overbuild stuff and it tends to last forever including a little extra abuse that tends to happen when I use things....
MartinDWhite wrote:This is going on a target rifle that won't be lugged around in the field, so I do appreciate the feed back on weight, but weight is not much of a concern for this build. A few threads I have seen in other places on recoil from 50 BMGs with suppressors vs. with muzzle breaks is that the suppressor needs to weight at least 6 lbs to provide similar recoil reduction as a good break. The target weight for this is between 7 and 8 lbs. I plan to make all the pieces, weight them, and go from there either reducing weight further or welding it together.
The aluminum spacer material is 0.128 wall thickness.
I tend to overbuild stuff and it tends to last forever including a little extra abuse that tends to happen when I use things....
My thoughts; The aluminum will be eaten away by the fiery hell inside the tube. FWIW
fastfire wrote:My thoughts; The aluminum will be eaten away by the fiery hell inside the tube. FWIW
It will take a while. The aluminum K baffles I used on my 223 took several thousand rounds to get gas cut. Another member here used SS for the baffles and aluminum for the spacers and did ok.
Ranb
SilencerTalk was a place I could disccuss making registered silencers without being told I was a criminal. That is no longer true. http://www.silencertalk.com/forum/viewtopic.php?f=132&t=99273
fastfire wrote:
My thoughts; The aluminum will be eaten away by the fiery hell inside the tube. FWIW
Aluminum for a baffle material might be a problem because the grains of power can embed and build up, or glance off and wear away the aluminum. I am using aluminum for the spacers and they are out of the line of the projectile and power grains until they have hit a steel surface first, they are 0.125 inches thick, and they are ~1.4 inches from the center line, I am not too concerned about them wearing away. I suspect they will wear minimally, if at all. If they do wear, enough to effect performance, it will take a LOT of shots.
I am leaning toward welding on the cap on the barrel end and threading on the cap on the exit end. This would allow me to take it apart to inspect for wear and clean it.
The plan for the baffles has solidified in my mind as follows:
Make a conical form from 3 inch stock with a 30* cone in the middle and a flat 1/2 lip on the outside edge. (here is a silly ASCII art representation)
_/\_
|__|
Make a mating upper half for the form. (here is a silly ASCII art representation)
____
|/\|
cut 4 inch squares from 0.125 flat plate.
heat the squares on a forge
press the plate in the form.....repeat for 8 more baffles. This will thin the material to around 0.100 (as a guess).
Mount the form in the lathe and cut a baffle's outside edge to round by using the forms to hold the baffle in place....repeat for 8 more baffles.
Mount a baffle in the lathe and bore the center hole to 0.550...repeat for 8 more baffles with hole size increasing to 0.610 for the last baffle.
Heat a baffle in forge and harden by quenching in oil or water....repeat 8 more times.
This should give me strong enough baffles with minimal material waste and the ability to make more if I do this again. Total cost should be just one piece of 0.125 plate, which I already have from another project.
Last edited by MartinDWhite on Thu Aug 13, 2015 1:45 pm, edited 1 time in total.
Half the baffle mold is complete. I guess it is really more of a die than a mold. The plate will be heated and pressed between this and the other half (which is getting made next).
The cones will measure 2.25" inside at the widest part of the cone and 2.5" just before the flat lip on the outside widest part of the cone. There will be a flat lip on each baffle to interface with the spacers. The ID of the spacers is 2.75".
The flat tip of the die is about 0.2". That means I can also make 30 cal baffles with this same die, if it works well....
Finished the die halves and just for giggles pressed a cold plate piece. I was pretty sure the metal would need to be heated to form correctly at such a steep angle, but I have formed 30* cones without heat so I thought this was worth trying. 20 ton press did as expected and deformed, then snapped the metal. I will build a forge or kiln next and try this again with glowing red metal plate.
I had the same problem. Never worked it out and cut the baffles from bar stock instead.
Ranb
SilencerTalk was a place I could disccuss making registered silencers without being told I was a criminal. That is no longer true. http://www.silencertalk.com/forum/viewtopic.php?f=132&t=99273
I am even thinking that you might need to press it in stages, maybe starting of with a big round nose and no hole in the plate. I think that relatively sharp point will always tear the plate if you start with a pilot hole. Good luck, I will be interested to see how you get on
Of all the things I've lost it's my mind I miss the most
I tried pressing in stages and while it worked better, I never got the full 60 degree cone I wanted. I wasn't able to heat my metal any hotter than I could get with a small propane torch, so better heat might make a difference.
Ranb
SilencerTalk was a place I could disccuss making registered silencers without being told I was a criminal. That is no longer true. http://www.silencertalk.com/forum/viewtopic.php?f=132&t=99273
6 fire bricks, some metal strapping, and a propane torch made a kiln. This got the metal sheet to glowing read and it pressed much easier.....BUT, it still ripped instead of formed. I think the dies were sucking the heat out of the metal and cooling it too fast. The next attempt will heat and form a little, then reheat, and form more.
This has become less about the end results and more about forming the metal for me right now.
MartinDWhite wrote:6 fire bricks, some metal strapping, and a propane torch made a kiln. This got the metal sheet to glowing read and it pressed much easier.....BUT, it still ripped instead of formed. I think the dies were sucking the heat out of the metal and cooling it too fast. The next attempt will heat and form a little, then reheat, and form more.
This has become less about the end results and more about forming the metal for me right now.
Hi,
Some industrial processes heat (or cool) the tooling, depending on what is required, could you play a gas torch on the dies to help the process, so they are already hot.
You could maybe have a mate play a gas torch on the pate/dies as you press it.
I guess after that is try a different grade of material, something like car body stock (get some from a scrap yard) is soft and ductile i.e. good for forming.
Keep me posted - good luck
PS I know what you mean, it gets to a point where you just don't want to be beaten
Of all the things I've lost it's my mind I miss the most
It has been a while and this project got shelved for a while because of the press forming issues. I gave up on the press forming and wanted a new plan....then A bunch of 3.35" aluminum rod came into my shop at a ridiculously low price, so I decided to make some of the baffles from that. The general plan is now a large blast chamber (7"-8") then 2 steel baffles and then 6 aluminum baffles to finish, with 1" between each baffle. The baffles are 0.200 thick in the cone and 30* cones. Any thought on the effectiveness of this?
I know aluminum isn't recommended for most rifle calibers, but anodizing or cerakote might help. I'm using preformed SS freeze plugs, 1.80 dia, from wedge machining. Mines a little goofy, I'm recessing the main tube into the expansion chamber and using a "gas stripper" baffle to try to limit the pressure on the baffles. Weights not a big issues for it's particular purpose, so I can build it a little heavier.
All the cutaway pictures I have seen of suppressors show the first baffle or two are very dirty and the rest are relatively clean. This has been my experience with my own also. So I think that since the first 2 baffles are steel they should take all the "damage" and the aluminum should be fine. Anodize is a good idea for the baffles. There is a local place that does hard anodize. I will get a price on getting these pieces done.
MartinDWhite wrote: ↑Thu Apr 16, 2020 1:30 pmThere is a local place that does hard anodize. I will get a price on getting these pieces done.
That's ok, but understand that these are silencer (firearm) parts and can't be left w/ just anyone. If they don't have the proper FFL license, you'll need to remain at the shop, until parts are finished. They must remain in under your control (possession).
Zero99z wrote: ↑Thu Apr 16, 2020 12:38 pm I'm recessing the main tube into the expansion chamber and using a "gas stripper" baffle
MartinDWhite wrote: ↑Thu Apr 16, 2020 1:30 pmThere is a local place that does hard anodize. I will get a price on getting these pieces done.
That's ok, but understand that these are silencer (firearm) parts and can't be left w/ just anyone. If they don't have the proper FFL license, you'll need to remain at the shop, until parts are finished. They must remain in under your control (possession).
Zero99z wrote: ↑Thu Apr 16, 2020 12:38 pm I'm recessing the main tube into the expansion chamber and using a "gas stripper" baffle
If you could provide a section view, I'm curious.
I'll have to draw it up this weekend. I used a first draft print to get a general idea, but it's time to do the final that has all the details. I'll get it posted in the next week.
MartinDWhite wrote: ↑Thu Apr 16, 2020 1:30 pmThere is a local place that does hard anodize. I will get a price on getting these pieces done.
That's ok, but understand that these are silencer (firearm) parts and can't be left w/ just anyone. If they don't have the proper FFL license, you'll need to remain at the shop, until parts are finished. They must remain in under your control (possession).
I'm super excited to see this project moving again! I recently completed a 30 cal suppressor from chromoly and stainless washers. It works so well I'm looking to start a form1 for my 50. Your posts have been very informative. I will need to use stainless freeze plugs and crmoly tube. My biggest struggle is lack of a lathe for threaded adapter end cap and not being able baffles. Advice/ suggestions appreciated! Please keep up the posts and images!
Milan.
MartinDWhite wrote: ↑Thu Apr 16, 2020 1:30 pmThere is a local place that does hard anodize. I will get a price on getting these pieces done.
That's ok, but understand that these are silencer (firearm) parts and can't be left w/ just anyone. If they don't have the proper FFL license, you'll need to remain at the shop, until parts are finished. They must remain in under your control (possession).
Zero99z wrote: ↑Thu Apr 16, 2020 12:38 pm I'm recessing the main tube into the expansion chamber and using a "gas stripper" baffle
If you could provide a section view, I'm curious.
It'll be mounted to a muzzle brake, but I haven't drawn that yet. It's an APA XXX bastard with a homemade qd mount directly behind it, extending over the barrel. 1 is the primary blast baffle/support that goes over over the tip of the brake. 2 is the "gas stripper" baffle. The baffle stack isn't drawn because I'm not sure how I'm going to stack them yet.
