ARMY SCHOOL OF MUSKETRY ?

[leigh kitchen]

That's what I'm thinking, commonly seen worn in WWI era studio photos.

[Toby Purcell]

Originally Posted by grey_green_acorn

Something like this?

Tim

The union clasp does seem the most likely in terms of common usage, especially if RND units were equipped from old stocks. I couldn’t understand at first the odd angle of the MG muzzles on the original image, but then realised he’s wearing a cap cover with the muzzles tucked underneath.