I was intrigued by the round count of the box.
The 48 rd box was a standard size in Canada 1940-55 for loose .303" ammo. The standard ammo crate held 26 of this size box at 100% capacity. Never saw WRA packed like that before.
Also standard size in Australia. The label suggests it could have been a contract for Britain or one of the Commonwealth countries.
This WRA 48-round box appeared for sale in the U.S. in the early 1960s at about the time the Lee Enfield rifles were imported from Britain. I have one of these boxes I likely saved simply because of the label; it contains small odds and ends I have also been unable to toss. Jack
The 48 round Box was standard supply for RAF RAAF etc. For use with linked belt loading machines;
Also for Loading Bren Magazines ( easier than 5 rd chargers)
Ball, Tracer, Incendiary, AP were supplied in 48s.
Early War Production had Red Printed labels, to differentiate from Land service ammo, then by 1943-44, all ammo was made to same Primer reliability standard, and the label printing was Green.
Sadly, all the US made boxer primed .303 in WWII, even the socalled Red Label for RAF use, was downgraded to Home Guard and Training use only because of ballistic unreliability ( loads, primers, cases).
A lot was still in stock when Interarms bought the entire UK inventory of .303 rifles and ammo in 1959.
This ammunition was packed in 1248 round wooden boxes (26 boxes of 48 rounds) and also in 336 round M1 metal boxes (7 boxes of 48 rounds). The latter are very hard to find.