Fuze Protector Cap Query

[jayp]

I believe this to be a fuze protector cap (see photo) and would like to find out which fuze it is designed to protect. As it is marked, No.5 Mk1 I had assumed that it was for the British No. 5 Pettman G.S. percussion, however, having now seen the size and shape of this fuse I think that most unlikely. The mark, S.M. I assume to be a manufacturer's mark, Singer Manufacturing perhaps? The protector cap is conical, 96mm long and 62mm dia. at the base. It is made of a light gauge brass, open at the base and with a 14mm dia. hole in the tip. Internally it has the remains of a lining, which looks like brown paper with a thicker white, hard (perished) substance to the lower third of the cone. Any help would be appreciated.

[peregrinvs]

My initial guess is that it's a protector for a WWII British No.199 time fuze - commonly used with the 3.7" AA shell. I can't find a reference to No5 Mk1 though.

[jayp]

My initial guess is that it's a protector for a WWII British No.199 time fuze - commonly used with the 3.7" AA shell. I can't find a reference to No5 Mk1 though.

Thank you, peregrinvs, for your reply. I read that the no.199 fuze began its development in 1925 and I wonder if my cap, inscribed no.5 mk1 dates from this development period before the fuse was adopted for use, and possibly only then officially numbered 199, just prior to WW2 ?

[peregrinvs]

I don't know I'm afraid. Try asking here: www.bocn.co.uk