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Thread: 3d printed shroud baffles.

  1. #1
    REP: Froggy Custom Silencers

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    Default 3d printed shroud baffles.

    I've been experimenting to optimize a design for 30 fpe + short barrel .bullpup.
    Sometimes I just want the rifle as compact as possible, if I can get it acceptably quiete.

    Tested in the P12 at 31 fpe... Barrel length 42 cm.
    All the inserts are the same 12 cm in length.
    I'll select the best design and test shorter lengths later.
    Tested indoors dry fired... Shooting a pellet reduces noise by about 1 dB... Doesn't make a huge difference.

    Rifle without factory cone end cap... 105 dB.
    With end cap 97. 5dB.

    First started with my normal design... Perforated with cone baffles wrapped with polyester batting.


    Unit just threads into the shroud.
    Shroud moved forward for 5 mm gap between insert and factory air stripper treaded to the barrel.
    94 dB..... Moved shroud forward 8 cm gap 89db. This design works best for lengths of about 20 cm.

    New design with 12 vent holes surrounding the centre hole.
    Air starts venting through the small holes first reducing back pressure and major air blast.
    5mm gap 91 dB.... 8 cm gap 89.5 dB.
    This design is very effective with a small gap, it gains very little when the shroud is extended.



    Painted black too see what it looks like installed.

    Different designs I've tested up to now.
    The white one with the large holes near the top baffle is the best performing.

    My large 20 cm 38mm diameter silencer.. 85 dB.
    Size difference..

    Gamo cf 30... 95.7 dB
    Dropping a coke bottle cap from waist height.. 83 dB.
    I'm very impressed how well 1mm pitch thread printed.
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  2. #2
    Marksman

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    Neat design and printing, I was wondering if the large spacing between baffles would effect accuracy due to the air velocity being higher than pellet velocity and essentially contained/guided towards the same direction of the pellet?
    What is your experience regarding spacing and accuracy?
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  3. #3
    REP: Froggy Custom Silencers

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    Still have to test accuracy. The only change might be to direct the venting air outwards and away from the pellets path.
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  4. #4
    REP: Froggy Custom Silencers

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    Filled the holes with powder to see how air flows. Couldn't get my timing right for super slow motion... Was taken at 120 fps. At least I can work out the time duration of the air blast by counting the frames.

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  5. #5
    REP: Froggy Custom Silencers

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    Now for accuracy testing I need to install my cz barrel. Been using the SPA barrel for sound testing.
    I didn't want to damaged the cz barrel with the grub screw retained P12 shroud fixture... The P12 air stripper thread is also different from my cz 1/2 inch unf.
    Designed these an printed them.
    The shroud can now be adjusted without marking the barrel.



    Checked for runout on the lathe... Very close to perfect.
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  6. #6
    Sharp Shooter

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    This is a very interesting and original take on shrouds and silencing. I congratulate you and admire the skill you display Froggy. I shall follow this thread with gret interest.
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  7. #7
    REP: Froggy Custom Silencers

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    Tried a few more designs... More baffles , larger venting holes, extra vents on the sides.
    This is the best performing so far.
    I dB quieter than the previous best, but more importantly is the tone of the report... The high frequency pitch is now gone.
    The rifle sounds louder from the shooter position, but is quieter in front of the muzzle.


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