It wont have been cordite, it would have been something else I forget the name now. Cordite is sticks, not powder. They loaded the .303 mk7 with nitrocellulose something or another powder since the start of WW1.
Cordite or Ballestite as a propellant was the first type of smokeless ammo - if you have the original 215 grain round nose bullet (mk6?) load pre WW1, then that will be loaded with actual cordite.
They used both cordite and nitrocellulose I have seen cordite loaded rounds wth a 64 data, The Greek .303 is loaded with ball powder, CAC 57 was definitely cordite we pulled the projectiles
from 300 of them to load in boxer primed new brass and modern powder it did work we got 1 MOA with a mint P14
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