The references I use are:
Regulations for Army Ordnance Services Part 6 Supply of Ammunition in the Field (8th August 1944)
Regulations for Army Ordnance Services Part 7 Pamphlet No. 1 An Introductory Survey of Ammunition (17th June 1944)
Regulations for Army Ordnance Services Part 7 Pamphlet No. 11 Small Arms Ammunition (24th February 1945)
My main reference is:
Royal Army Ordnance Corps Statistics Pamphlet No. 2 Weights and Measurements of Explosives (21st June 1943)
The reference as published isnt onlne but
this link should show what I've been able to put together so far.