7.62X51 NATO

7.62 NATO

The 7.62 NATO also known as its metric nomenclature; 7.62x51mm, is a .30″ caliber, rimless, bottleneck cartridge case design, centerfire rifle cartridge. The 7.62 NATO cartridge casing is reloadable after the cartridge has been fired or spent with various combinations of primer, powder and .308″ diameter bullets.

Cartridge Specifications: Bullet Diameter – .308″. Primer Diameter – .210″. Primer Type – Large Rifle. Case Neck Diameter – .343″. Case Shoulder Diameter – .454″. Case Base Diameter – .471″. Case Rim Diameter – .473″. Min. Case Length – 2.005″ / Trimmed. Max. Case Length – 2.015″ / Stretched. Min. Cartridge Loaded Length – 2.490″. Max. Cartridge Loaded Length – 2.810″. Max. Average Pressure – 60,200 PSI.

Rifle Specifications: Rifling Twist Rates – 1 in 12″. Bore Land Diameter – .300″ / 7.62mm. Bore Groove Diameter – .308″ / 7.82mm. Headspace Go Gauge – 1.6350″. Headspace No Go Gauge – 1.6405″. Headspace Field Gauge – 1.6455″.

In 1954, the 308 Winchester or 7.62x51mm cartridge would be adopted by NATO and the cartridge would also be known as the 7.62 NATO cartridge. Rifle chambers are then modified slightly to eliminate feeding issues in the United States Rifle – 7.62 mm – M14. Maximum cartridge pressures would also be reduced slightly.

During the 1940s and early 1950s several experiments were carried out to improve on the M1-Garand. One of the most common complaints was the limited capacity en-bloc clip and many experimental designs modified the weapon with a detachable box magazine.

The test program continued for several years, including both the original .30-06 Springfield round and a modified 300 Savage (then known as the T65). In the end, the T65 cartridge demonstrated power roughly equal to the original .30-06, firing a 147-grain bullet at 2,750 feet per second but was approximately .5 inches shorter. The eventual result of this competition was the T44 rifle.

The T44 was adopted as the M14 in 1957. The M14s would later go through several variations intended to either limit fully automatic selection through semi-auto version or selector locks or improve control with bipods and/or heavier barrels.

The 7.62 mm cartridge was introduced in U.S. service in the M14 rifle and M60 machine gun in the late 1950s. The M14 and many other firearms that use the 7.62 NATO round remain in service today, especially in the case of sniper rifles and machine guns. The cartridge is used both by infantry and on mounted and crew-served weapons mounted to vehicles, aircraft and ships.

The 7.62 NATO centerfire rifle cartridge is a rifle cartridge developed in the 1950s as a standard for small arms among NATO countries. When a cartridge is loaded with a bullet design that tumbles, or fragments in tissue, this cartridge is capable of delivering good terminal wounding performance for sniper, military and police use.

U.S. Military 7.62 mm Ammunition:

M61: 150.5 grain bullet, 7.62 mm NATO, armor-piercing round, black cartridge tip.
M62: 142.0 grain bullet, 7.62 mm NATO, tracer round, orange cartridge tip.
M276: 150 grain bullet, 7.62 mm NATO, dim tracer round, green cartridge tip with pink ring.
M118 LR: 7.62 mm NATO, 173 Grain Bullet, 2,580 Feet Per Second Muzzle Velocity, 2,557 Foot Pounds Muzzle Energy.
M80: 147 grain bullet, 7.62 mm NATO, lead core ball round 2,733 Feet Per Second Muzzle Velocity, 2,438 Foot Pounds Muzzle Energy.
M80A1: The 7.62 mm M80A1 cartridge projectile is lead free and features a three-part bullet consisting of a steel penetrator, a copper slug, and a reverse-drawn copper jacket. It is environmentally-friendly and designed to provide improved lethality compared to the M80 ball cartridge.

The 7.62 mm M80A1 cartridge is compatible with: M240 series machine guns, M134 “mini gun”, Mk48 machine gun, M110, MK17, M40A5 and M14.U.S.

7.62X51 Headstamps

FA – Frankford Arsenal.
AO or KS – Allegheny Ordnance Plant.
DEN – Denver Ordnance Plant.
DM – Des Moines Ordnance Plant.
EC – Evansville Ordnance Plant.
ECS – Evansville Ordnance Plant (Sunbeam).
EW – Eau Claire Ordnance Plant.
KOP – Kingsbury Ordnance Plant.
LC – Lake City Ordnance Plant.
LM – Lowell Ordnance Plant.
M – Milwaukee Ordnance Plant.
P, PC, PCC – Kings Mills Ordnance Plant.
ROP – Redstone Ordnance Plant.
SL – St. Louis Ordnance Plant.
TW – Twin Cities Ordnance Plant.
U or UT – Utah Ordnance Plant.

For 7.62X51 and other rifle cartridge ballistics, make sure you check out our chart by pushing on that link.