Marking in British Fuze no 80

[no3nh4]

Hello.
A model 80 British fuze bearing these marks has fallen into my hands: Number 57 inside a circle and An "A" inside a "C"

Can someone tell me its meaning?
Thanks in advance and greetings

 

[Snufkin]

It is a broad arrow within a letter C, denoting acceptance of a Canadian manufactured part. The bottom section is the fuze socket or adapter that enables the fuze to screw into the Shrapnel shell body. The 57 in a circle appears to be an inspection stamp, and it appears it was common practice on Canadian made sockets to have two such stamps, one either side of the acceptance broad arrow.

 

[no3nh4]

thank you very much for your reply, Snufkin.