The headstamp would suggest a 1940 date - my guess is BN is thr MFR. - the green bandoliers are marked BN and there is none of the typical US nomenclature stamped on the bandoliers, just a circle with an "X" and B and N on it. My guess would be foreign but a manufacture date of 1940 makes no sense at all for foreign Garand ammo and certainly no foreign powers were putting 06 in enbloc clips in 1940.
Whuzz it?!?