Building our first .223 suppressor

[Zerbiak]

Hey all,

I work in a fabrication shop up here in Alaska and a couple of my coworkers and I decided we wanted to try our hand at building our own suppressors. In Alaska, as long as its completely made in here and stays here, we do not need to fill out all the legal mumbo jumbo, so we figured what the heck. I have been stalking some of the threads looking for different design ideas and we think this ( http://imgur.com/HBzAx64.jpg , http://imgur.com/j0D2W6h.jpg , http://imgur.com/GuUqgv4.jpg) may be one to pursue. I have since chopped off the .375" combined at the ends and filled them in with the end caps. Those were wishful/ over complicated engineering thinking. The mono-core baffle we were going to machine from 1.375" 316L stainless, along with the end caps. For the can, we were going to use 1.50" .065 wall 4130 tubing. According to solidworks, with the materials I listed, the total mass of the assembly is about 1.75 lbs. The front end cap could either be welded or threaded in place, we weren't picky with that one, but we did want the barrel attachment side removable so we could fit it on a .22 if we wanted. If all works fine, I'd make separatebaffling for my 22 so my .223 baffling doesn't get damaged.

A few things I would like to know are: what an average muzzle pressure of a .223 is (for FEA), what a good bore size would be for the baffling, and what y'all think. For some reason, I have yet to find what bore size folks use for .223 suppressors. Since this is my first stab at designing a suppressor, I am totally open to suggestions. Thanks guys!

[Dr.K]

How do you circumvent federal law in Alaska?

It makes no sense to me. You did get a stamp first, right?

[300sniper]

It is because of the Firearms Freedom Act. While I agree with it, I sure wouldn't want to be the crash test dummy on this one. I don't think I'd advertise it on the WWW.

[Zerbiak]

http://www.legis.state.ak.us/basis/get_ ... session=26 here you go. Section 44.99.500 spells it out in suprisingly clear terms that if its made here, stays here, and is marked made in alaska, everything is copesetic. The state attorney general even has to defend our right to do so. A machine shop called trijet out of Palmer are selling their own lower recievers specifically to Alaskans for Alaskans with no federal interference. As long as it has the cool little polar bear made in alaska stamp, its cool.

[Zerbiak]

It is because of the Firearms Freedom Act. While I agree with it, I sure wouldn't want to be the crash test dummy on this one. I don't think I'd advertise it on the WWW.

The first shot is definitely what im most nervous about. Im going to try and do as much analysis on the thing as I can before we even begin. Why wouldnt you advertise it on the web though? The law is common knowledge and there to be utilized by folks like my friends and me who have the means to do this kind of stuff. AK is a pretty individualistic friendly place.

[Dr.K]

Well fhuck me! Good for you guys! Im too close to the freaking Nazi's.

I have used clipped cones with fantastic success.

[Capt. Link.]

5.56 is a high pressure round.4130 threaded 28tpi with a minimum of .050 wall is sufficient .065 is better.I bore .060 over bullet size of .224 but if you have everything inline with low run-out a smaller bore will work.Don't expect silence using super sonic ammo as the sonic wave cannot be suppressed.I would add more baffles to increase suppression.Your choice of carbon steel is wise under the cold temperatures you can see there but beware of the corrosive environment inside a suppressor caused by the nitric acid residue.Make sure that the barrel threads are concentric to the bore and the shoulder is square.Check the tightness of the can often as they tend to unscrew.Good luck and keep us posted!

[Zerbiak]

Capt. Link, thanks for the info! We should be able to keep tolerances +- .015 at the very least with our machining abilities here or if we decide to get the baffling machined elsewhere it should be similar. I fit as many baffles in there as I was comfortable having while maintaining about a 1/16 inch of material through the baffles, but I have One concern. Since I dont know a decent average for the muzzle pressure, im not sure what kind of space I need at the blast baffle. The material thickness at this point is about .125 inches but im not sure what kind of area the baffle needs. I wanted to make sure there was plenty of area for the gases to expand out of the barrel. I suppose I should have mentioned before hand that I have pretty much zero personal experience with suppressors but I did graduate with a degree in mechanical engineering so I understand most of the technical side of things haha.

[silencer_kid]

Well fhuck me! Good for you guys! Im too close to the freaking Nazi's.

I have used clipped cones with fantastic success.

you didnt know this? i am shocked.

How do you circumvent federal law in Alaska?

It makes no sense to me. You did get a stamp first, right?

because they know more about it then you do.

[Dr.K]

Well fhuck me! Good for you guys! Im too close to the freaking Nazi's.

I have used clipped cones with fantastic success.

you didnt know this? i am shocked.

How do you circumvent federal law in Alaska?

It makes no sense to me. You did get a stamp first, right?

because they know more about it then you do.

FFS dude. I'm from Louisiana, so of course I don't know Alaska state laws. What the hell is your problem?

I hope they do know local laws, it's something most of us consider important.

Quit being an assclown.

[silencer_kid]

Well fhuck me! Good for you guys! Im too close to the freaking Nazi's.

I have used clipped cones with fantastic success.

you didnt know this? i am shocked.

How do you circumvent federal law in Alaska?

It makes no sense to me. You did get a stamp first, right?

because they know more about it then you do.

FFS dude. I'm from Louisiana, so of course I don't know Alaska state laws. What the hell is your problem?

I hope they do know local laws, it's something most of us consider important.

Quit being an assclown.

your 1st reply to the OP was "... ...You did get a stamp first, right?".
geez, everything with you is a form-1 and stamp.
sure, i stopped assclown when i signed up on this site.

how about skipping the legal advice and just answer his Q's

[Dr.K]

Capt. Link, thanks for the info! We should be able to keep tolerances +- .015 at the very least with our machining abilities here or if we decide to get the baffling machined elsewhere it should be similar. I fit as many baffles in there as I was comfortable having while maintaining about a 1/16 inch of material through the baffles, but I have One concern. Since I dont know a decent average for the muzzle pressure, im not sure what kind of space I need at the blast baffle. The material thickness at this point is about .125 inches but im not sure what kind of area the baffle needs. I wanted to make sure there was plenty of area for the gases to expand out of the barrel. I suppose I should have mentioned before hand that I have pretty much zero personal experience with suppressors but I did graduate with a degree in mechanical engineering so I understand most of the technical side of things haha.

If you are using it on an AR, or other semi auto, you need a little more room for expansion, to decrease blowback. With a bolt gun it doesn't matter that much. I put my blast baffle 2.25" away from the muzzle with a thread on can.

Pressures will vary with barrel length, with a 16" or greater barrel in 556, 0.125" seems a bit overkill for wall thickness. I over engineered my first one as well. I use 0.070" now.

I wouldn't just cram as many as possible as far as baffles go, spacing is important. I make mine so that the first chambers are larger and the ones at the end of the can are tighter. ranging from an inch, down to half inch at the end.

Hey, silencer kid. Shut up.

[gunny50]

hey, silencer kid. Shut up.

That is good advice, 2" to 2,5" blast / expansion chamber with 1" to 0,5" spacing to the back will do a good job. Clipped cones are a solid performer for 556. If you deside to make a 2nd stack for 22 go K.

Gunny, ( in vegas )

[ChimeraPrecision]

Capt. Link, thanks for the info! We should be able to keep tolerances +- .015 at the very least with our machining abilities here or if we decide to get the baffling machined elsewhere it should be similar. I fit as many baffles in there as I was comfortable having while maintaining about a 1/16 inch of material through the baffles, but I have One concern. Since I dont know a decent average for the muzzle pressure, im not sure what kind of space I need at the blast baffle. The material thickness at this point is about .125 inches but im not sure what kind of area the baffle needs. I wanted to make sure there was plenty of area for the gases to expand out of the barrel. I suppose I should have mentioned before hand that I have pretty much zero personal experience with suppressors but I did graduate with a degree in mechanical engineering so I understand most of the technical side of things haha.

I bet if you take your time, and use sound metrology you can achieve something much closer to +/- .005.

Good luck, I'm glad someone is running with the FFA

[Zerbiak]

Capt. Link, thanks for the info! We should be able to keep tolerances +- .015 at the very least with our machining abilities here or if we decide to get the baffling machined elsewhere it should be similar. I fit as many baffles in there as I was comfortable having while maintaining about a 1/16 inch of material through the baffles, but I have One concern. Since I dont know a decent average for the muzzle pressure, im not sure what kind of space I need at the blast baffle. The material thickness at this point is about .125 inches but im not sure what kind of area the baffle needs. I wanted to make sure there was plenty of area for the gases to expand out of the barrel. I suppose I should have mentioned before hand that I have pretty much zero personal experience with suppressors but I did graduate with a degree in mechanical engineering so I understand most of the technical side of things haha.

If you are using it on an AR, or other semi auto, you need a little more room for expansion, to decrease blowback. With a bolt gun it doesn't matter that much. I put my blast baffle 2.25" away from the muzzle with a thread on can.

Pressures will vary with barrel length, with a 16" or greater barrel in 556, 0.125" seems a bit overkill for wall thickness. I over engineered my first one as well. I use 0.070" now.

I wouldn't just cram as many as possible as far as baffles go, spacing is important. I make mine so that the first chambers are larger and the ones at the end of the can are tighter. ranging from an inch, down to half inch at the end.

Hey, silencer kid. Shut up.

First off, I'm kinda sad... I wrote a whole long response on my phone and the site logged me off in the middle of it. Lost it all.

As for the 2 - 2.250 inch blast chamber, why so much out front? I worked extra area into the barrel attachment cap to make up for some area being soaked up out front. Just curious. I believe the total area I have for the blast chamber is more or less equivalent to that of 2.250 inches out front. I would have to look at the drawing again to make sure though. As of my latest iteration, I believe I have 1.9375 in front of the barrel and a bit of extra space out behind where the barrel attachment.
For the baffles, I considered stacking them with staggered distances, but I figured more material created by stacking them evenly would mean overall better sound suppression. I suppose though, sound travels slower through gases than solids. Is that the reasoning? I would like to try and understand as much about these devices as possible before I go and stick one on the end of my AR.
Also, after a few beers at Alaska's best brewery (Midnight Sun Brewery, seriously, you wont want to leave Alaska after you've tried their beer and food) I can confidently say, Silencer_Kid you are coming across as a pretty limp dick. Don't be THAT guy bro. Dr. K was curious as to how I was able to circumvent federal law and I answered him politely. Alaska State Law is usually not common knowledge to non- Alaska state residents. Seriously... go back to 4chan or reddit if you want immature, smart ass retorts.

[Zerbiak]

Capt. Link, thanks for the info! We should be able to keep tolerances +- .015 at the very least with our machining abilities here or if we decide to get the baffling machined elsewhere it should be similar. I fit as many baffles in there as I was comfortable having while maintaining about a 1/16 inch of material through the baffles, but I have One concern. Since I dont know a decent average for the muzzle pressure, im not sure what kind of space I need at the blast baffle. The material thickness at this point is about .125 inches but im not sure what kind of area the baffle needs. I wanted to make sure there was plenty of area for the gases to expand out of the barrel. I suppose I should have mentioned before hand that I have pretty much zero personal experience with suppressors but I did graduate with a degree in mechanical engineering so I understand most of the technical side of things haha.

I bet if you take your time, and use sound metrology you can achieve something much closer to +/- .005.

Good luck, I'm glad someone is running with the FFA

I am not the one who is going to run the lathe, so I cannot determine how my buddies will do on the tolerances. None of us is a master machinist and our shops master machinist made it clear he wasn't gong to help us. (Old hippie...) If we do end up getting the baffling and end caps made elsewhere, I will work in some pretty close tolerances and geometric tolerances. I think the tolerances I state on our drawings for the shop on machined parts is +/- .005 on 3 decimal place dimensions unless otherwise stated and that is what I would go with. The hardest part for us in the shop would be radius's. We have a digital readout on our vertical mill, but it would probably still be hard/ time consuming getting really close tolerances on hand made parts.

[Dr.K]

When you say area I'm thinking you mean volume. When there is volume available behind the muzzle that is referred to as a "reflex" design. The same volume behind the muzzle is not as effective as it would be in front. That is why you don't see that design as often.

The "why" is because if there isn't enough expansion volume, the pressure goes thru the gas tube, around the bolt carrier, thru the crack in your charging handle, and ultimately burns your eyes....well, irritates them some. Lol.

With a closed action, no big deal. The pressure drop is substantial when the bullet uncorks. I don't have real numbers to throw around, but it is several thousand psi.if memory serves right.

[doubloon]

... I sure wouldn't want to be the crash test dummy on this one. ...

Me either but I will donate to his legal fund if necessary.

[Zerbiak]

Ahhh. Ok, makes sense. I did mean volume btw. I'm firing on Friday night brain cells, not Tuesday morning engineer brain cells. I will have to check my drawings again. I cannot remember off hand exactly how much space I have out front of the muzzle. I can certainly skooch the attachment point back some, that's easy to change. I had the attach point further forward so I could keep the CG closer to me rather than way out front. None of the drawings I have made thus far have been complete because things keep changing. I haven't wanted to do the hole gambit for dimensions in the drawings, haha.

[Dr.K]

Don't sweat it, ALL of my drawings are freehand on one of those pads with the quarter inch blue squares all over them....Oh, and a greasy old half sized spiral notebook that does double duty as my reloading information storage facility, ha ha.

My hats off to you guys busting out the 3d stuff via computer.

However, if it came to a race.....He'll, I'll just ask.
How long does it take to do one of those pretty computerized 3d blueprints, drawings, schematics, or whatever its called?

[Zerbiak]

ummm... With the individual parts, I have the end caps set up on a revolved extrusion so all I have to do is fiddle with the original 2d drawing for a second or two and things are changed how I want them. The baffling is just an extruded cut drawing on top of a 1.375 rod and a few other cuts. Easy Peasy. Drawings are slightly different, but definitely easier than doing it by hand. SolidWorks allows me to import the solid model into the drawing and use all its dimensions to define how things should be. I have way more respect for y'all who do it by hand than us computer jockeys. Computers make things easy. I can have a rough flow simulation done in less than 5 minutes while the fluid mechanic calcs for such a thing may take weeks. My designs are really fluid in my ability to change how they interact with each other. One thing I have tried to become proficient at is streamlining adjustments in overall assemblies rather than changing things individually. Relations and the equation editor in SolidWorks are amazing.

[silencer_kid]

CAD is the only way to go. this may or may not be my design (less the internals, cant show that here, those are secret secret).
ViaCAD Pro v8 is a good consumer grade program, also easy to lean.
Zerbiak seems to be looking at the physics of it all. i wonder how many people here actually understand the physics in a silencer, or do they draw and cut? the latter method is likely to have high probability of failure.



and just a tidbit on ViaCad. its one of the top ranking consumer level products out there for both 2d & 3d work. very easy to learn. if you buy online be sure to look for coupons 1st and apply what you can for most savings. ViaCAD however lacks the big professional features of AutoCAD, Solidworks, etc, but for most consumer grade projects ViaCAD should do the job. the $69 2d/3d version is good for doing can designs, but i bought Pro for some of the additional features.

[twodollarbill]

http://www.legis.state.ak.us/basis/get_ ... session=26 here you go. Section 44.99.500 spells it out in suprisingly clear terms that if its made here, stays here, and is marked made in alaska, everything is copesetic. The state attorney general even has to defend our right to do so. A machine shop called trijet out of Palmer are selling their own lower recievers specifically to Alaskans for Alaskans with no federal interference. As long as it has the cool little polar bear made in alaska stamp, its cool.

Have I been sleeping in a cave since I got back to the states.

Alaska is exerting the right under the Constitution to accept/require compliance to only those FEDERAL laws that were enacted prior to its (Alaska's) accepting statehood.
That means that the MG law of 1934 does apply, but the Gun Control Act of 1968 does NOT!
Alaska has taken the position that any Federal law enacted AFTER Alaskan statehood does not apply to them if they deem it to be contrary to the U.S. Constitution.

Simply Awesome

[Flat Tire]

http://www.legis.state.ak.us/basis/get_ ... session=26 here you go. Section 44.99.500 spells it out in suprisingly clear terms that if its made here, stays here, and is marked made in alaska, everything is copesetic. The state attorney general even has to defend our right to do so. A machine shop called trijet out of Palmer are selling their own lower recievers specifically to Alaskans for Alaskans with no federal interference. As long as it has the cool little polar bear made in alaska stamp, its cool.

Have I been sleeping in a cave since I got back to the states.

Alaska is exerting the right under the Constitution to accept/require compliance to only those FEDERAL laws that were enacted prior to its (Alaska's) accepting statehood.
That means that the MG law of 1934 does apply, but the Gun Control Act of 1968 does NOT!
Alaska has taken the position that any Federal law enacted AFTER Alaskan statehood does not apply to them if they deem it to be contrary to the U.S. Constitution.

Simply Awesome

I have read that Idaho has this "Made in Idaho" law as well, I don't trust it. From my point of view Fed Law is the law of the land. $200 bucks for a Form 1 is cheap insurance and a lot cheaper than any attorney I have ever dealt with.

[Zerbiak]

http://www.legis.state.ak.us/basis/get_ ... session=26 here you go. Section 44.99.500 spells it out in suprisingly clear terms that if its made here, stays here, and is marked made in alaska, everything is copesetic. The state attorney general even has to defend our right to do so. A machine shop called trijet out of Palmer are selling their own lower recievers specifically to Alaskans for Alaskans with no federal interference. As long as it has the cool little polar bear made in alaska stamp, its cool.

Have I been sleeping in a cave since I got back to the states.

Alaska is exerting the right under the Constitution to accept/require compliance to only those FEDERAL laws that were enacted prior to its (Alaska's) accepting statehood.
That means that the MG law of 1934 does apply, but the Gun Control Act of 1968 does NOT!
Alaska has taken the position that any Federal law enacted AFTER Alaskan statehood does not apply to them if they deem it to be contrary to the U.S. Constitution.

Simply Awesome

I have read that Idaho has this "Made in Idaho" law as well, I don't trust it. From my point of view Fed Law is the law of the land. $200 bucks for a Form 1 is cheap insurance and a lot cheaper than any attorney I have ever dealt with.

Idaho's firearm accessories law legislature.idaho.gov/idstat/Title18/T18CH33SECT18-3315A.htm if you are interested. You shouldnt have anything to worry about if you keep it in state. And why giv the fed more money? Seems silly to get a form 1 if you dont need to