The 7mm Compromise (T65 / 7mm):

In 1952 after the NATO trails it became clear that the United States would never adopt the .280/30 Enfield round.The reason for this refusal was the lack of power compared with the .30-06 round (the service round of the U.S. army at that time and used as a reference) and the American experimental T65 cartridge.

In an attempt to increase the performance of a 7mm round the Canadians (as member of the BBC committee) developed the 7mm Compromise. They used the American T65-E3 cartridge case, necked it down to 7mm. The Compromise was loaded  with a full range of bullets like the Belgium  S12 and the Brittish type AA.

The 7mm Compromise is produced in the United Kingdom, Belgium and Canada.

The ballistics of this cartridge were not very good, because of the strong angled neck of the case. With the belgium S12 bullet the muzzle velocity was about 2800 fps. (for the .280/30 is the M.V. 2415 fps)

7mm Compromise, (.280/30 and 7.62x51mm for comparison)            Ball type A and type S12 (7mm Mauser type)

headstamps:DAC 50, FN 52, RG 53

The 7mm Compromise was never approved for service.