Air Rifle Silencer Suppressor Moderator

Edit 14 Feb 2023 I now use a short 5 baffle silencer without the extension baffle fitted onto the original mederator using my sleeve adaptor. I do not use the any bore washers now as they did not seem to make a difference.

Edit 05 Feb 2023
Added 7mm bore washer rather than 5.5mm bore as these were too small.
Have also added my own threaded end cap threaded for 1/2 UNF x 20 but have increased the thread minor diameter from 8.33 to 8.88 which fits perfectly on my Remington Airacobra PCP. Also increased the endcap diameter slightly to match the black Screwfix Push fit pipe I am using. The end cap has holes for 4x 2mm grub screws or allen bolts.
I have included the STL & FreeCad file if anyone needs to adjust the thread. You will find it under Vthreadprofile-Minor diameter in FreeCad.

You will need the Thread Profile addon in FreeCad. https://github.com/mwganson/ThreadProfile

Also added a pushfit silencer to fit over the original Airacobra silencer. I plan to try a shorter silncer without the extention baffle but using the prefitted silencer as a pre-silencer.
Freecad and stl files included if you want to try the same on your rifle. Print the slot-on adapter with the larger diameter circle on the printbed and add supports from the printbed at 5%.

When printed squeeze the support in your hand and it will drop off.

I print the parts at 40%.

On initial testing the trigger mech operating made more noise than the pellet discharging.

Original Text

A few added files to go with the original silencer https://www.thingiverse.com/thing:2586045
This is still a protoype and will post test results once I get round to testing sound moderation using a dB meter.

Files included are a grubscrew template front and rear for accurately drilling 4 pilot holes on each end to take screws to clamp the end caps in place. When you have finished using them as drilling templates they can be used as caps to cover both ends of the silencer when not in use.
To use the drilling template push onto the bare tube with no end caps in place. Drill 1mm pilot holes though the template holes into the tube ready for final drilling to fit your grub screws or bolts.
I have used M2 x 5mm allen head bolts. After pilot drilling the holes in the main tube I then fitted the end caps on the tube and drilled 1.5mm holes through the tube into the end caps. The M2 bolts will self tap in this hole. The main tube was then drilled out to 4mm to hide the M2 bolt head once fully tightened up.

I have added wahsers with reduced 5.5mm holes for 0.177" pellets (waiting to test these) to see if this reduces the sound compared to the current 9mm holes. These fit in between each baffle.

A new end cap with 5.5mm hole is included to match the washers for 0.177" caliber pellets.

Once tested succesfully I will add 0.22" caliber end cap and washers.

The silencer uses black 40mm push fit pipe from Screwfix.
The silencer is 248mm overal length and weighs in at 168g with 7 baffles an extention baffle and 7 1mm washers.

The pipe used is 241mm.

Once tested with various combinations of baffles washer and bore sizes I will reduce the silencer length to suit.