This is a fully functional Air rifle suppressor and is extremely efficient. Its about twice as effective as the stock Air arms suppressor on my AA 410 TDR. It should fit most of the AA range as they all seem to use the same suppressor fitments. The 1/2" UNF variant should work on any rifle that has that fitment.
It also has fully balanced baffles to ensure zero pellet deflection. You can choose to print the whole thing in one go by using the Silencer.stl file or print the front and rear then glue/weld them together. I recommend using ABS for stability and strength but PLA will work and solvent welding using either Acetone or MEK. If you want the 1/2" UNF version it is only available by printing SilencerRear and SilencerFront_UNF then welding. Please be careful when welding the halves that you line up the internal square sections as the initial expansion volume runs around the outside of the rear to maximise available volume. It doesn't matter which faces line up as long as the squares align.
I haven't tried it on a .177 - It should work "as is" but the through hole should be reduced in diameter by 1.0mm to optimise. If you do try it let me know what it's like.
Its easy to print and doesn't require any supports (I designed it that way) and print it solid. Print it so it stands up with the large diameter where the pellet comes out on the print bed in all cases. Don't print it lay down.
You will probably want to put a 8mm twist drill through the pellet path just to clean up any debris/strands of material.
You will need to drill and tap a hole for a grub screw to attach it to an Air Arms or you will need to tap the 1/2" UNF thread. I didn't bother modeling a screw hole for the AA version and the chances of successfully printing 1/2" UNF I considered rather limited. With the 1/2" UNF version I modeled a 11.5mm hole ready to tap.
Before welding/gluing the halves together clean up the faces to make sure that there are no lumps or bumps which may affect alignment. Put a straight edge along the sides to check. If you aren't sure you can align everything when joining the halves a good tip is to lay the halves in a piece of right angle section.