One must also recall that Finland used up a lot of Italian Wartime-Supplied 7,35x51 M38 ammo to make 7,62x39 Long Blanks, and even some Ball cases. This was during the early period of the acceptance of the Valmet M72? Assault Rifle (Finn upgrade of the Kalashnikov).
It was also the time Finland was retiring its older Fighter Planes, fitted with .303 MGs, and so, despite the big sales of Milsurp .303 to Interarms, they still had sufficient of it (VPT marked) to “break it down” and re-use the cases, by Turning and full sizing to make wood bullet blanks.
WE at AV Blankfire use a similar method to make various full length blanks from existing, other calibre ball cartridge cases
( eg, 6,5 Japanese from 30/06 or .270; 7,62x39 from .220 Swift,(or .303) for long blanks; 9,3x74R for 7,7x58SR Japanese long (for Type 89 Pan magazine.) The one which most closely mirrors the 303/7,62 conversion, is making .30 Carbine long blanks from 5,56x45 Cases, by re-drawing the case, trimming, sizing, and recutting the extractor groove.
We also have other fabrication methods for making successful “Long” Blanks, but they are not pertinent to this discussion.
AV Ballistics Film Ordnance Services
AV Blankfire P/L