Oh dear, now you've got my brain on full ahead invent. I have never seen a a shotgun head wad, but I believe I have a bagfull of felt wads that would do very nicely in an M-H case. White felt, 15 mm outer diameter, hole in the middle about 7 mm diameter. So the annulus is about 4 mm thick. Thickness of wad 5 mm. What is it? - The felt wad that is used under the guide pin on piano keys to dampen the impact on the keyboard frame, that's what. So nowall you need is a supply of scrap pianos...

Seriously, I reckon such a felt ring is spot on as a head wad.

Just one thought - what happens to a head wad when the gun is fired - does it burn, smoulder or what? What does that mean in terms of re-using cases? I presume that anyone who is not a multi-millionare IS re-using their M-H cases.

Patrick