Monolithic baffle stack

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.

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Davo5o
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Post by Davo5o »

WoW!! I like. That should hold a lot of water for a long time, and keep it real nice and quiet. Thanks for the pics.
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hotbrass
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Post by hotbrass »

how do you machine those inside right angles?
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Post by Mageever »

Hey Conq', cool idea! You know.... you could extrude that and then cut it into cross sections. Bamm! Massed produced! Don't forget to drill a bore hole and some threads, of course. :D While you are at it, you could extrude the outer tube that would simply slip over it. Extra cool. 8)
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Conqueror
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Post by Conqueror »

hotbrass: Wire EDM. Neither of those stacks could be made with only a mill and lathe.

CQ
gelandangan
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Post by gelandangan »

hotbrass wrote:how do you machine those inside right angles?
use EDM or waterjet
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CONKLE73
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Post by CONKLE73 »

I was kicking around this idea of “linear baffles” for a 9mm mono-baffle for my 9mm AR-15 and wanted to see what you guys think.

1.5” 303 stainless bar stock center bored to the proper diameter for 9mm (I was thinking .4104) then bore holes from the outside of the stock through to the bored centerline at 60deg to the center line of the bore at regular intervals along the longitudinal lined of the stock at 0, 45, 90, 135, 180, 225, 270 and 315 degrees. Then cut longitudinal flutes along the same lines to act as chambers.
I’m no machinist, so my description might not be the best, but I hope that you get the idea.

Latitudinal cross section + Longitudinal cross section:


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K2unit
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Post by K2unit »

Here is a Form 1 Approved Alien Arms prototype...

K2 Unit/ Alien Arms
www.alienarms.com

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wolf
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Post by wolf »

What caliber ,,and how does it compare to knowns designs ??

Isnt the dirt build up on the threads going to make it hard to unscrew ??
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CONKLE73
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Post by CONKLE73 »

I drew one up similar to that for a Form-1 9mm can…
Cool idea of yours, attaching to the receiver like a barrel nut…
Curious how effective it is.



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tacticalmachining.com
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Post by tacticalmachining.com »

hotbrass wrote:how do you machine those inside right angles?
You could do it on a mill, but it would be slow. Chuck up a lathe bit of HSS with square corners the width you need to cut the top and bottem of each slot's corners at the same time. Grind some relief along the sides of the bit. Lock the spindle of the mill so it won't spin. Drive it up and down by hand to use the lathe bit as a broach (DO NOT turn on the mill!). It would cut out each pair of corners. You can cut a square hole out of a round one in this manner as long as it is not to deep because the longer bit's will flex to much.

Homemade falling block rifle actions are sometimes made like this to get the square hole needed through the action.
jamesmcintosh
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Post by jamesmcintosh »

How much clearance/play is needed between the monolithic baffle stack and the can?
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Baffled
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Post by Baffled »

I don't know how much is "needed", but the concensus seems to be less is better. I have maybe 0.012" between stack and wall, large enough so that I don't think I have to worry about being unable to take the can apart.

I think that's a good number. I get the feeling that the gas, in squeezing though that boundary layer, does a lot of work and loses energy rapidly through the stack body and tube wall, yet the gap is large enough so as to not overly hinder the gas flow. I hope that makes sense... it's early! :D
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Post by jreinke »

Conqueror wrote:Here's my design for a mono stack. Similar to Baffled's, but with larger coaxial chambers for increased volume. I also cut the "mouse holes" straight with a larger endmill, which leaves a sharp ledge in the round chamber which should "cut into" the swirling gas like the ledge on a coach's whistle, helping it flow quickly into the coaxial chambers.

Image

I wish I still had access to a machine shop, I would gladly Form 1 this stack to try it.
Conqueror,

I'm in the process of doing a mono stack can entirely out of 17-4PH stainless and I'm leaning on trying your whistle method of porting to the coaxial chambers rather than drill holes like Baffled did. In the pictures above, which way did you envision the gas flow from, left to right or right to left? BTW, my tube has an OD of 1.120" and an ID of 1". My stack has 8 offset chambers 5/8" dia with 8 coaxial chambers with an 11/16" radius.
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tnrcboatracer
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Post by tnrcboatracer »

Sorry to resurrect an old thread, but I'm reading up and trying to learn as much as possible. On the subject core, were the second set of mouseholes ever added and tested? What about adding a second mousehole from the outer chamber perpendicular to the bore intersecting the edge of the baffle into the downstream chamber. IE, the first mouse hole is at 60 angle into the outer chamber, and a second mousehole at 90 intersecting the leading edge of the next downstream baffle. The purpose of the second mousehole is to add a turbulence jet at the next baffle to direct the gas jet toward the 60 mouse hole. Thoughts?
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Post by BKE520 »

Heres my take on a design for a monocore, I forgot to put the vent holes in to let gases into the outer chambers but thats easy. I left a little rib along the top to add rigidity if I use aircraft grade aluminum. I want it to be as light as possible but I dont want it to crush. I also thought about getting a chunk of titanium if its not too hard to machine, I havent had much experience with machining anything other than aluminum. If I could get it light enough id try for stainless as a last resort, the outer tube will be a slip fit with O-rings and a threaded cap. Should be pretty simple to do on the CNC.

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I do like the guy that just drilled a bunch of holes in a piece of metal lol. Kind of rough but shoot... it works. Only downside to that is it looks heavy which would only be cool on a rifle that you bench rest and I am looking at putting this on a 22 pistol. The wall thicknesses on this is approx 0.06" between the baffles, 1" OD, 6" long. Hopefully I get around to building it, I need a 22 pistol first.... Out of all the guns I have, I havent gotten a 22 pistol yet.
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Post by Mageever »

BKE520 wrote:Heres my take on a design for a monocore, I forgot to put the vent holes in to let gases into the outer chambers but thats easy. I left a little rib along the top to add rigidity if I use aircraft grade aluminum. I want it to be as light as possible but I dont want it to crush. I also thought about getting a chunk of titanium if its not too hard to machine, I havent had much experience with machining anything other than aluminum. If I could get it light enough id try for stainless as a last resort, the outer tube will be a slip fit with O-rings and a threaded cap. Should be pretty simple to do on the CNC.

Image

I do like the guy that just drilled a bunch of holes in a piece of metal lol. Kind of rough but shoot... it works. Only downside to that is it looks heavy which would only be cool on a rifle that you bench rest and I am looking at putting this on a 22 pistol. The wall thicknesses on this is approx 0.06" between the baffles, 1" OD, 6" long. Hopefully I get around to building it, I need a 22 pistol first.... Out of all the guns I have, I havent gotten a 22 pistol yet.
Cool design. The overall diameter has to be about 1.375-1.500, right? That might seem a little large in diameter for a .22 pistol. But if you are going to use it for an all around .22 rifle/pistol platform it should have great performance. I'm assuming your design is similar to mine in how the tube will slip over the core and then have an end cap screw on. Looks like you got the additional rib for support on the secondary chambers like I recommended, so the only key thing I'd add is this....put the second O-ring on the cap, NOT the core. The first time you go to slide that tube off and it has to travel all the way over that end O-ring (while being gummed up with crud) you'll realize what I meant.

I entertained the idea of a titanium core, but when I realized how hard it would be to machine on a manual mill I decided to bag it. Also, few realize this, but it will weigh more than aluminum. The only advantage I could find would be that you can safely do the chemical bath to clean it.
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Post by tnrcboatracer »

I'm doing the same thing with the CNC and a rib down the side through secondary chambers, but since I'm planning on doing a 5.56 can for a 10.5"SBR, I was thinking of a hybrid design with a steel/titanium blast chamber with conical deflector that telescopes 3~4" over the end of the bbl like a Reflex, followed by a 4 chamber monolithic core. The walls on my mono core are 0.093" with 0.125" between the primary chambers. It will have 2 mouseholes per chamber; 1 @ ~30* to the bore axis, and 1 @ 90* that intersects the entrance to the downstream primary chamber to work the gas flow like a K baffle. I'm looking at an OD of 1.75"~2.0" with an OAL of ~8". Regarding the chamber offsets; I used a bore of 0.250" and offset the chamber so that there is a 0.015" clearance to the bore hole at the max tangent. Is the 0.25" bore too small for the 5.56? Would 0.260" be better? (I wish I could model it in 3D, but I'm not that good, I just do 2D CAD; A.K.A. an electric pencil) I can write my own G-code, though.
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Post by dave22 »

For a .22 I think you could make it 1" dia and it would still work great. I don't think the reinforcing ribs are needed at all, they are just taking up space for a .22 you will have plenty of strength. That would also make it easy to do the mouse holes on an indexer, all in one setup.

Just my opinion of course. I like that design and would not be surprised if you find some manufacture making it in a year or two.

*edit* Oops I just re read your post looks like it will be 1" OD. I must have mis read that.

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Post by Mageever »

tnrcboatracer wrote:....Would 0.260" be better?...
Yep. You might be able to get away with .250 for a while, but it could eventually catch up to you. One really cool aspect of this design is the inherent accuracy of the threads to bore relationship. Do it all in one pass and you'll have what some manufacturers don't have because of the slop you get from assembling pieces with tolerances. I think the first few chambers in mine were in the mid-.250's somewhere. Can't remember offhand but it's in my old topic.

I like the idea of what you said about re-routing the gasses back in. I didn't on mine because of the "unkown" factor. If you do it and it doesn't help then you're kind of screwed. The single holes I did were even a little large I think. I wished I had started really small and kept drilling them bigger while listening for an effect.

Regarding ribs in the secondary chambers-- they are actually pretty important because when you remove that much material then you have a really strong structure in one direction (side to side) but a weak structure in the other direction (top to bottom). Mine will noticably flex in this one direction if you begin to pry on it.

BKE--is that drawing really only 1" OD?? Those must be teeny chambers with a really tight bore. It's a real geometric balancing act to get the chambers offset enough to work while staying within the .900-.920" dia.
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Machine Gun Matt
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Post by Machine Gun Matt »

CONKLE73 wrote:I was kicking around this idea of �linear baffles� for a 9mm mono-baffle for my 9mm AR-15 and wanted to see what you guys think.

1.5� 303 stainless bar stock center bored to the proper diameter for 9mm (I was thinking .4104) then bore holes from the outside of the stock through to the bored centerline at 60deg to the center line of the bore at regular intervals along the longitudinal lined of the stock at 0, 45, 90, 135, 180, 225, 270 and 315 degrees. Then cut longitudinal flutes along the same lines to act as chambers.
I�m no machinist, so my description might not be the best, but I hope that you get the idea.

Latitudinal cross section + Longitudinal cross section:


Image

Image



Here is a Form2, 9mm mono stack before it was finished.

Its made using 304 ss with a 1.500"dia tube. OAL is about 7.500"

Bore is .404 dia., threaded 1/2"x28 and .625x24 end cap.
The end cap was threaded in this fashion so that an extension (another can) could be threaded on for further sound dampening when a compact package wasn't needed.

This stack was tested on a Swedish-K. Certainly hearing safe (dry) using 147gr. subsonic ammo, 115gr Wolf and some of the open bolt only 115gr. corrosive ammo designed for cold weather. The action of this weapon makes this gun difficult to suppress.

I took a Soumi barrel and threaded it 1/2x28 tpi just forward of the barrel shroud. minor fitting was required on the O.D. of the barrel so it would fit in the Swedish K trunion.

Also ran the can wet with approx. a tablespoon of water with great sound reduction. Sound reduction was good for about 28 of the 36 rounds in the magazine on full auto.

First round pop was all but eliminated when run wet. Dry it was pretty loud. :roll:

Tested it at night and flash was reduced dry and wet even the ejection port flash was minimal.

IMHO the can could/should have been made of Aircraft Grade Aluminum as it was really heavy. But with the corrosive ammo its easier to clean.

Also tried it on a 11.5" M-16...... and its far from being hearing safe or reducing muzzle flash. It did however reduce the sound signature.

Both weapons were obviously easier to control (see suppressor weight)

Not pictured is the groove for the O-ring (machined after pic) and I also reduced the oal (.625) end where it threads onto the barrel.

Put it on the 10/22 and worked pretty good as well.

Was a fun exercise.



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killerofall
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Post by killerofall »

I like the way you have theaded that, Interesting idea.
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Post by BKE520 »

If I did that ribbed silencer design out of titanium I would think about losing the ribs, but if its out of aluminum, I would run a test piece with a few holes in it to see the rigidity. I dont trust the aluminum to hold up, I think its going to stretch, bend, or do something that would get the center hole off center. I also thought if I did do the rib, that I would do a dual mouse hole in kind of a V pattern since I would not be able to drill straight down, dont think it will improve anything, just something kind of unique.

I just picked up a ruger 22/45. I have thought about threading the barrel but I heard of a guy that made a silencer for his ruger MK III where he made his silencer slightly larger than the barrel, approx 0.200" overall, then milled a slot that corresponded to his front sight post so that when he slipped it over the tip of the barrel, he could rotate it into place. He supposedly had a spring in there to add the tension needed to keep it in place. There was a kind of keyed notch to keep it from twisting off. Has anyone done this before? I only see it working on guns like the ruger 22 pistols, or the buckmarks, or a variety of rifles since most pistol barrels do not extend out like that. I also thought of drilling a hole on the underside of my barrel for a tiny stud that would lock into place in the same way that the front site did, that would keep it from torquing against the barrel. Ill see if I can get some pictures if no one knows what the hell im talking about. I could probably work something up in CATIA.

The small threaded end cap on that silencer is nice, I might have to do that instead of the big end cap like I was thinking of doing. I hate threading stuff.... I would just like to see him remove all that extra metal on that supporessor, it would be a boat anchor if its used on a pistol. Im always trying to think "keep it as light as possible" when I am building racecars so thats the way I am thinking with suppressors.
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Post by BKE520 »

Forgot to mention about the use of titanium, I was planning on using a 1/4 inch endmill in a CNC. If I slow the machine down enough it will do an awesome job, at least that is what I am hoping since I havent really messed around with titanium very much. I thought of doing a bit of hand filing inside the secondary chambers to square the radius's under the ribs since I cant use an 1/8" endmill on titanium reliably. I dont know how well a waterjet works on a piece of barstock, but I thought it would be awesome if it worked good to get some nice sharp corners to maximize the volume. If anyone has waterjetted a piece of round stock, id like to hear how that worked for them.
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Post by BKE520 »

Message #3 today... I decided to throw together a rendering of what I was talking about. Instead of threading the barrel I would use the front site as one of the attachment points, then I would drill a hole in the bottom of the barrel to hold a pin which would be the locking mechanism and another means of attachment. The guy that did something similar to this supposedly had a spring in there to keep the suppressor in place. The picture on the left is suppose to be the suppressor and the picture on the right is the barrel on a MK III ruger 22/45. The dimensions are approx accurate but this was just thrown together in a few minutes. Any better ideas instead of using a spring or has anyone seen this done much before? You cant tell from the picture but the bottom slot has a radius that would lock that pin into place to keep it from rotating while shooting. Dont want your suppressor to fall off.
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este
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Post by este »

Does anyone have a chart of caliber per recommened design ?

For instance, k-baffels for .22 pistol, or .3 and larger you should use a monocore or etc etc

What is the monocore used best for ??? .22 .223 .308 etc ?

Is there a rule ? What is jreinke's design best for ?

I've been looking to do a .308 can on Form1 but I'm not sure if I should be looking at reflex or k or m or mono etc....

Ideas ?
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