end cap insert

I’ve seen a few tests like that on U-Tube… the most successful demos seem to use a wall or fence as a sound reflector. The camera records the echo…. longer echo means louder, short echo means quieter.

F R,
is there room to wrap felt around the outside of it , the part that goes is the frame.

just a hint….the frames vay greatly in inside diameter….so if your going to make one that you sell to people, i would recommend that you use an oring in each end with enough play, that tight frames can squese the orings and keep centered…and so that large frames the oring simply center it

problem is as soon as you tighten the frame cap screw it might push the mod upwards…..

maybe just offer different sizes, or an drill attachment, so people can mount it in a regular drill and just use a bit of sandpaper to fit it

i have made a very similar device…they work great

ohh you can make the bore holes large enough that even if its slightly off center the pellet wont clip….maybe something like a .308 hole….i would go .25 and machine it to fit my rifle perfectly….but you intend to sell…and the crappy AF tolerances makes it kind of difficult….