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Tell me why this suppressor design won't work

Discussion in 'NFA Weapon Discussion' started by Dyjital, Nov 20, 2014.

  1. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    I know NOTHING but what I have read. I have no world experience, never shot one, never held one.

    I'm bit by the bug now and am looking at January to submit a Form 1 and build a suppressor for a .357 Rossi that I have.

    Idea is to slow down the escaping gas... so after looking online at many, many designs of monocores, baffle designs I've come up with something similar to one that I've seen online that a person made.

    The idea for me on this is that i'm not a skilled lathe operator, but could make baffles as I have the ability to do whatever I put effort into..

    The image is just the monocore. It would be drilled with the same pattern at 90 degrees, so think of it like drilling two sides of a rectangular piece of steel.

    I would make it from stainless steel, between each hole there would be a minimum of say .1-.2" of material on outer edge. Excuse the drawing, I could make a better one on the computer if I spent more than a couple minutes on it.

    Idea would be to start with a large cavity that's 80% of the width of the core. Then I would step it down to 75% for the next holes until I started to walk towards the end of the core and at that point I would probably have a 50% hole. if I used 1.5" diameter stock, 50% would be a 3/4" hole, 75%=1-1/8" etc..

    From what I gather when a form 1 is submitted you specify length, and caliber, without needing to give specific details about baffles etc. So if this design flopped I would have an outer that I could manufacture a new inner correct?

    Excuse the dimensions, they aren't exact nor is everything next to each other like I wanted.
    Suppressor Design.jpg

    for clarification:
    Suppressor Design.jpg


    Be gentle, correct me easily... Thanks in advance.
     
  2. TapRackNGo

    TapRackNGo PNW Well-Known Member

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    If you take apart a suppressor you will find the baffles look similar to a flashlight bezel. That is pretty much how most are made more or less. Personally, I wouldn't try and re-invent the wheel. that looks like it would probably work tho. I do believe some suppressors have little ports within the bezel to help displace gas.
     
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  3. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    Yeah I've sketched K-baffles, watched maybe two hours worth on YouTube on making them. My issue is the large I have access too is an old one so when it comes to making fine adjustments via a digital readout it won't happen. Everything on this one is dials and gauges. I don't want to oops on a baffle.


    I'm thinking though that every 3rd hole I drill needs to have a gap because otherwise it would be a straight through pass for the gas.


    Maybe I'll make one in Sketchup tonight and give myself a 3d view of a 2d design.

    I sure don't want to reinvent the wheel here. Just need to minimize lathe time.
     
  4. TapRackNGo

    TapRackNGo PNW Well-Known Member

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    I don't have any that come apart, but I'm sure you can find some videos online. Good luck!
     
  5. jbett98

    jbett98 NW Oregon Bronze Supporter Bronze Supporter

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    I'm curious, why a .357 Magnum and not something that lends itself to sub sonic loads?
     
  6. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    Why? I can. I reload and .357/.38 shoot from same gun.

    I can load .357's at 1000fps with reasonable 0-100 accuracy and I know drop to 200yds. I've loaded some that are almost as quiet as .22LR's.

    I also load .38's that you can almost shoot without ear protection.
     
  7. jdub75

    jdub75 PNW Well-Known Member

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    There are some very active threads on AR15.com relating to form 1 suppressors...you're likely to learn a lot if you spend some time over there. I've been kicking around the idea myself lately, and have found the posts useful.
     
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  8. Reno911

    Reno911 Hillsboro Well-Known Member 2015 Volunteer 2016 Volunteer

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    Your design has been done. The only problem would be not enough space for expanding gas. Your cross cut sections would need to be opened up for expanding has to dump into.

    See the second pic.

    ImageUploadedByTapatalk1416535234.590604.jpg
    ImageUploadedByTapatalk1416535248.156828.jpg

    Most home made suppressers use multiple cone baffles spaced apart. This is the same as most manufactured cans. It optimizes space pretty well.

    You need to catch, keep, and redirect as much gas as possible. Drilling a few circular holes into bar steel is a start. Opening up the remaining space and porting it together correctly is the challenge.
     
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  9. Reno911

    Reno911 Hillsboro Well-Known Member 2015 Volunteer 2016 Volunteer

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    Also if you form 1 it and machine a threaded cap. Serialize the cap, not the sleeve, monocore, or end cap.
     
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  10. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    Thanks. I see that the design needs a modification.

    I really appreciate that second photo. It shows me the error.

    Seriously. Much appreciated.
     
  11. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    @Reno911
    Bullet path is green

    So what I was lacking was the red path for the gasses to escape the primary chamber to be captured in the secondary chamber. Holes to be drilled at 45* from CL.

    Suppressor Design.jpg

    Also quick Q: Why scribe the cap? (as in the end that attaches to the firearm).. is that to ensure that if a modification needed to be made you aren't breaking the law by remanufacturing a piece that you already serial numbered and marked? Or if you wanted to interchange a different baffle design or different caliber etc?
     
  12. rutilate

    rutilate Vancouver and Surrounds Active Member

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    Exactly. If the cap is serialized you can repair / modify the internals without a $200 fee and six months wait time.
     
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  13. Reno911

    Reno911 Hillsboro Well-Known Member 2015 Volunteer 2016 Volunteer

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    Your on the right track. Cool thing is you can start small and always open up those holes to allow more gas in seeing if it will suppress better.

    By serializing the cap, everything else is a part. If you wanted to change out the monocore later for a new design. You could. If you get a baffle strike you could replace it. Etc, you get the idea. May not want to have a bunch of parts lying around though. It still can be considered intent when you got one stamp and enough parts for 8 suppressers. However if you toss the monocore, or destroy it for another, your good.

    Also if your going the multical route, file the form for the largest caliber you plan on ever using it for. Ie if you drill the end plate for 30 cal, file for 30 cal. If for any odd reason you get audited, they are going to see a 30 cal hole and be asking why you filed a 22 cal can.
     
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  14. AMProducts

    AMProducts Maple Valley, WA Jerk, Ammo Manufacturer Silver Supporter

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    I don't know what your machine shop capability is, but rather than drilling the red holes, I would mill it on the edges. I've done this before and it works really well.

    During my tenure for a former employer (10/02 FFL) we had a fair amount of time to experiment with a number of suppressor designs the good ones would be registered, the bad would face the saw.

    Your initial design seemed fairly sound, I'm not 100% sure why you varied the hole sizes

    Here's a .22LR monocore I designed a while ago. I have built one of these I didn't show the threading but it did work quite well and it was fairly light. it's 5" long, and 1" OD
    22MonoCore.PNG

    22MonoCore.PNG
     
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  15. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    @AMProducts the idea behind the smaller holes at the end was to force more of the slower moving gases to the capture cutouts on the outside.

    All theory of course.

    Im also going to be doing this sans cnc or mill.
     
  16. AMProducts

    AMProducts Maple Valley, WA Jerk, Ammo Manufacturer Silver Supporter

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    Yes, I realize your rational for the holes... however if you offset them it becomes more effective

    Most suppressor designs rely on some kind of symmetry, mostly I think it's more a reflection of the humans that created them liking symmetry than it actually doing anything. If you look at the above design, if you see the cuts on the side facing you. Those are not symmetrical (no cuts on the other side) Most of my suppressor designs have counted on two ideas: Gas under high pressure will move more mass through an aperture than a low pressure gas will. I realize this sounds somewhat terse, but the idea being if you fill a volume with a gas at 200 PSI through a .1" opening as the pressure drops, so the time for that gas to empty that volume will also increase. The second idea is that as the time it takes to release the pressure is increased, the lower the impulse will be. (Impulse = noise)

    There are some other tricks you can play with harmonic shifting, but it's pretty complicated science.

    So if you don't have a mill, do you at least have a lathe? In all honesty, without a mill, all of these designs will be very difficult to realize and I would suggest simplifying the design significantly. Perhaps even going to one of the more primitive freeze-plug style suppressors. They do work and can work well, but more modern designs can be made smaller and more durable.
     
  17. Gun Mechanic

    Gun Mechanic Portland Active Member

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  18. AMProducts

    AMProducts Maple Valley, WA Jerk, Ammo Manufacturer Silver Supporter

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    Gun Mechanic likes this.
  19. Nickb

    Nickb Moxee Active Member

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    I don't know much about suppressors. To me it seems a lot easier to go with cones, rather than drilling a straight hole 10 inches long.
     
  20. Dyjital

    Dyjital Albany, Ore Flavorite Member Bronze Supporter

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    Yeah have a lathe accessible, I've found the ways to do what I need with what I have. Takes an extra step but it doesn't need a more expensive machine.

    I'll do some more research regarding flow and such. I have plenty of time to do that.

    I could draw up the way I plan to do it without cnc, just requires two dead pieces on each side as this will start as square stock and be turned down after the holes are drilled. Easier to work without cnc using squares vs cylinders. :)


    In summation, need to redesign, off set holes, keep same diameter and keep reading.... Maybe find a program to test fluid dynamics..... :)

    Also keep in mind I do this to test the limits of what I can do with what I have. I could just buy an econo-can and make my suppressor screw to the end of that, either way I'm still making my own stuff. (Though not sure of the legality of adding anything beyond the econo-can)