Just compared the rounds these are all 7.62.
This might be a long shot... and I could be totally mistaken but here's a suggestion.
The brass casing does appear to be .303 British. 7.7mm is the correct metric size for .303 bullets which would compare almost identically if not exactly to a 7.62mm bullet.
That the label says Flying Troops and might be armour piercing if they are indeed British makes me wonder if they were meant for British .303 Browning machine guns. Finland purchased twelve Hawker Hurricane fighters in 1940. The Hurricane was armed with eight .303 machine guns in its wings.
Hurricanes to Finland
They are most definitely .303 British, also known as 7,7x56R. Close to Mosin 7.62x54R, but not the same....
The other British aircraft armed with .303 caliber machine guns flown by the Finns were Bristol Blenheims. Some were built under license, Nazi captured Yugoslavian aircraft were given or sold to Finland and some were obtained from Britain. The armament of BL 200 is given as .303 caliber machine guns.
Ilmasotakoulun Kilta | Bristol Blenheim Mk IV BL-200
So sorry guys! When I was comparing the rounds I grabed the ones marked VPT 40. Witch are %100 7.62. I just grabed the VPT 41 and they have a longer neck I took some photos comparing them.
First round is current .303
Second is VPT 41
Third is VPT 40
Fourth is current 7.62
Sorry again guys I did not compare the VPT 41 to 7.62 till right now. Thanks for your patients with me