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Thread: Supressor design question

  1. #1
    ebf
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    Supressor design question

    So from my internet research and measuring various suppressors I have at home, it looks like the norm for center-fire can is 1.5 inch / 38mm diameter minimum. My DPT cans are 44mm diameter.

    For rimfire can it is less, typically 25mm to 30mm, so around the 1 inch mark.

    I have a Bergara BA13 in 308 that I would like to use with open sights. When I screw on my DPT center-fire can, the 44mm diameter makes the front sight blade disappear. I only intend using the suppressor for sub-sonic ammo, not my normal super-sonic 168 Amax load.

    So I have 2 options, either raise the sights, or decrease the can diameter.

    I guess my question is, how small a diameter can you go to assuming similar wall thickness ?

    Pressure wise, I have got @Puffin to run some simulations in QuickLoad. His version did not have TrailBoss, but we got a similar load using ADI AS50, driving a 152gr cast projectile to 1050 fps out of a 16.5 inch barrel with 1:12 twist. Peak pressure looked like 10,000 psi, and muzzle pressure around 2,000 psi.

    If you compare that to peak pressure for 22lr @ 24,000 psi, it would seem reasonably safe to consider using a rimfire can (bored for larger projectiles, doh) for sub-sonic loads only out of the 308 ???

    Interested to hear comments or real-world experiences

    @gundoc
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  2. #2
    Member Micky Duck's Avatar
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    I BELIEVE the internal VOLUMN is going to be the most important ,more than the pressure...the bigger the can the more room the hot exploding gases have to do their thing,thus why the bigger cans are the quietest.... gunworks do a skinnier version of the spartan..MAYBE you could get a slightly longer one and be good to go.
    the magnum rated cans are large...the .223 sort not so much..your .308 will be burning much more powder so SHOULD need more room to put gases....it will always be louder as the hole in the end is bigger so more noise will escape...I have theory that a layer of insulation tape helps no end in reducing that first shots noise.comparing rimfire can to centrefire can the rimfire is less than half the size so it follows its only got half the room for gases.
    mucko and Moa Hunter like this.

  3. #3
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    If you have lots of money to throw at it, I'd have a bash at an eccentricly machined supressor, ie, the top of it will be inline with barrel and the chamber/volume is hanging below.
    Couple existing designs like this, slip-on rimfire and a 12ga shotgun one.
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  4. #4
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    The secret to efficient suppressor design is volume above all else. Baffle design (despite the opinions of many) is largely irrelevant provided the design traps gas reasonably well. As you do not intend to run full-power supersonic loads then gas volume generated is going to be much less and a smaller suppressor will still work. I think a modified .22 suppressor will still be too small to offer much suppression of muzzle noise. A 38mm can about 150mm long would be the absolute minimum you should consider, and 200mm would be better. At that size there would still be noticeable muzzle noise but well within your comfort level. I think your choice of bullet weight is too light and would suggest a minimum of 180grains and preferably a bit heavier. It depends what your intended target is but a good rule of thumb with subsonic loads is to replace velocity with bullet weight! My favourite .308 subsonic load is 12 grains of Winchester Super Target and a 220 grain RNJSP (about 1050 fps). I do not use any fillers in my subsonic loads but your choice of powder should be fast burning and fairly bulky. Many shotgun powders are eminently suitable.
    Bill999, ebf, Tasbay and 7 others like this.

  5. #5
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    You could help by porting the underside of the barrel, but this is obviously going to give you muzzle flip when shooting without supressor, and if prone is going to blast dust and shit all round the place
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  6. #6
    ebf
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    Quote Originally Posted by mimms2 View Post
    If you have lots of money to throw at it, I'd have a bash at an eccentricly machined supressor, ie, the top of it will be inline with barrel and the chamber/volume is hanging below.
    Couple existing designs like this, slip-on rimfire and a 12ga shotgun one.
    Yup, that was suggested by someone else on here that I had a phone conversation with.

    It increases the complexity in terms of machining by a good amount. Can has to be indexed for correct alignment. Baffles have to be bored off center, and I would need to find a way of keying or securing them in the correct orientation.
    Viva la Howa ! R.I.P. Toby
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  7. #7
    Member Micky Duck's Avatar
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    those higher sights be looking pretty good right about now......how much higher are we talking??? 5-8mm or more ????
    a taller blade and the rear elevated by same amount,hopefully without having to change it out...

  8. #8
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    Quote Originally Posted by ebf View Post
    Yup, that was suggested by someone else on here that I had a phone conversation with.

    It increases the complexity in terms of machining by a good amount. Can has to be indexed for correct alignment. Baffles have to be bored off center, and I would need to find a way of keying or securing them in the correct orientation.
    That's why I said it wouldn't be cheap. Eminently doable though.
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    Name:  DSCF2104.JPG
Views: 281
Size:  2.97 MB Just off centre the barrel. 44mag and PVC with alloy plate baffles. Don`t over think it.
    Bill999, Mintie and r87mm like this.

  10. #10
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    Yeah what he said. Pin the baffle stack so they are fixed in place with a key inside the tube so it can't sod off, or monocore it using a solid block machined with and offset hole that's threaded. Glue and screw the outside tube on...

    I got a 44 cal can here which is just an empty tube I was thinking of doing something like that with it.

  11. #11
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    You could go longer and smaller diameter to get your volume
    Gunworks are a lot smaller diameter wise than Dpt
    Non concentric would be cooler tho

  12. #12
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    I just got higher sights on my A7 ..works.
    Micky Duck likes this.

  13. #13
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    Thicker is better then longer.

    Much more volum by using a thick silencer.

    Suppresor A: 8cm Diameter and 10cm length has a 500cm3 volume.
    Suppresor B: 4cm Diameter and 20cm length has a 250cm3 volume.

    So, short fat... or long fat.


    This is a Norwegian silencer. Optima 60 is just 16mm thicker then Optima 45, but 6db or 4x more suppression.

    Optima 45 - 44.4mm diameter - 29 dB (230mm length) 320cm3
    Optima 60 - 60mm diameter - 35dB (230mm length ) 650cm3

  14. #14
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    Quote Originally Posted by ebf View Post
    So from my internet research and measuring various suppressors I have at home, it looks like the norm for center-fire can is 1.5 inch / 38mm diameter minimum. My DPT cans are 44mm diameter.

    For rimfire can it is less, typically 25mm to 30mm, so around the 1 inch mark.

    I have a Bergara BA13 in 308 that I would like to use with open sights. When I screw on my DPT center-fire can, the 44mm diameter makes the front sight blade disappear. I only intend using the suppressor for sub-sonic ammo, not my normal super-sonic 168 Amax load.

    So I have 2 options, either raise the sights, or decrease the can diameter.

    I guess my question is, how small a diameter can you go to assuming similar wall thickness ?

    Pressure wise, I have got @Puffin to run some simulations in QuickLoad. His version did not have TrailBoss, but we got a similar load using ADI AS50, driving a 152gr cast projectile to 1050 fps out of a 16.5 inch barrel with 1:12 twist. Peak pressure looked like 10,000 psi, and muzzle pressure around 2,000 psi.

    If you compare that to peak pressure for 22lr @ 24,000 psi, it would seem reasonably safe to consider using a rimfire can (bored for larger projectiles, doh) for sub-sonic loads only out of the 308 ???

    Interested to hear comments or real-world experiences

    @gundoc
    irrespective of diameter the can should contain the volume of gas produced by the load, baffle design can assist with this as well. the suppressors i make for my self are 50mm for centre fire and 32mm for .22 but i over barrel them as much as i can.
    Moa Hunter likes this.

  15. #15
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    Some good ideas here & off set is nice, be good to know what you want to do with it, eg shot bailed pigs or home kill cattle or ..... ?

    But above most of that listen to @gundoc lol !

    8.5gr to 14gr of some type of fast burning powder is all up need to trap in your can & the heaviest bullet is best !

    400gr to 550gr big flat meplat in a .45 (45/70) is best killer no doubt, in my option .

 

 

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