British trench mortar fuze cartridge

Just adding some pics of a cutaway of this 303 cartridge from the inside of a British ww1 trench mortar fuze.The detonator and paper tube are encased in a cardboard tube inside the cartridge..Does anyone know if theres a reason the paper tube is chequered ?? or is it just using whatever was available..
cartridge headstamp E 17 VII

Very nice Spotter, I have to say if I'd found one of those in a militaria fair I wouldn't have had a clue what it was for. Nice to see all the info with it.

Dave.

Does anyone know if theres a reason the paper tube is chequered ??

I have seen these chequered tubes on 9mm flobert rounds. I wonder if theres a connection?
Hangarman

Although the case is headstamped by Eley, that does not necessarily mean the detonator was loaded by them. However, if it was, then they probably just used the paper tubes they would have used for rimfire shotshells pre-war.

The same applies if the case was shipped to Kynoch, Kings Norton or whoever for loading.

Regards
TonyE

Does anyone have a complete strippable example of the fuze this cartridge was used with,as im looking for a clear picture of the part circled in the attatched post.(from different angles if possible please)..
allan