WW1 18 Pounder Manufacturer

[gremlin666]

Can anyone out there please identify the manufacturer of this WW1 18 Pounder Shell
Its a heavy type Mk IX Shrapnel Shell, stamped C.S.B.Co. and picked up in Canada so assume its almost certainly of Canadian or US origin

It has double broad arrows and stamped:

Q.F. 18PR
IX
F.S.
C.S.B.Co.
21 5 17
I A

 

[Snufkin]

C.S.B.Co. - Collingwood Ship Building Co., Canada.

 

[gremlin666]

Thanks so much Snufkin. Clears that mystery up