7.62mm NATO
Although often referred to as the 7.62x51mm, the correct name for this round is the 7.62mm NATO since they are manufactured to STANAG 2310.
By the early 1950s it was abundantly clear that the American ordnance authorities, led by the Chief of Ordnance Col, Rene Strudler, were going to accept nothing less that a full powered .30 inch round as the new NATO standard infantry cartridge. This was despite the previous recommendations of the U.S. Army testing board that the British .280 inch solution showed the most promise and should be the basis for further development.
The American proposal was based initially on a modification of the .300 Savage commercial case and had been developed by 1953 into the 51mm long T65E3 case with both lead and steel cored ball bullets and a range of tracer, AP and incendiary..
U.S. Drawing of the T65E3 case.
The American cartridges that were entered in the final 1953 BBC (Britain Belgium Canada) trials were the T104E2 Ball, T101E1 AP Incendiary, T102E1 Tracer and the T93E1 and T93E2 Armour piercing.
As it became evident that the .30 inch Light Rifle cartridge was to become the new NATO standard, both ICI Kynoch and ROF Radway Green prepared for pilot production. It was at about this point that the round was renamed the 7.62x51mm..
It was agreed to accept the U.S. T104E2 as the new standard general purpose (ball) round but the U.K. elected to produce the lead cored Belgian S77 bullet which had been agreed as an acceptable substitute for the T104E2 because of ease of manufacture.
Drawings to British standards were produced of the T65E3 case (D6/L/1277/E/88) and the Belgian S77 bullet (D6/L/1299/G/88) together with the complete round which was provisionally designated Ball L2A1 (D6/L/1311/GF/88).
By late 1953 ROF Radway Green had produced the first Berdan primed examples of the T65E3 case.
Nomenclature
It is worth noting some points regarding the nomenclature of the 7.62mm round. It was the first round to be allocated the new NATO "L" numbers instead of the traditional British "mark" numbers and introduced certain subtle differences.
One of these was the distinction between bulleted and unbulletted ammunition. Ammunition without a bullet (e.g. blanks) had the nomenclature "Cartridge 7.62mm...." whilst that with a bullet (ball etc. including drill) became "Round 7.62mm....".
Certain authorities have stated that the "L1" slot has been allocated twice in error (grenade cartridge and drill) as has "L14", (Practice ball and blank). In fact the error is theirs as the grenade cartridge is "Cartridge 7.62mm Rifle grenade L1A1" since it has no bullet whilst the drill is "Round 7.62mm Drill L1A1" as it has a bullet. Similarly the blank is "Cartridge 7,62mm Blank L14A1" whilst the practice ball is "Round 7.62mm Training, Short Range, L14A1".