Any cartridge can be adopted to fulfill the requirements of a sniper cartridge. In fact, the rifle itself probably is what contributes more to the accuracy of the shot than what it is chambered for. For most nations the main rifle cartridge adopted is the cartridge used for sharpshooting, designated marksman (DM) and snipers. In today’s climate you have either adopted the 7.62 NATO or the Russian 7.62x54R as your primary accuracy cartridge. The civilian version of the 7.62x51mm is the .308 Winchester. In competition the .308 has earned a reputation for accuracy and precision.
If loaded properly the 7.62 Russian can shoot fairly straight, but the weapons chambered for this round like the Dragunov sniper rifle has been more attractive as a DM rifle. The older weapons were not tack drivers, but sufficiently accurate for combat out to some 5-600 meters. Modern versions have tightened their groupings considerably. With groupings of 2 MOA (Minutes of Angle) it made hits beyond 600 meters problematic with the older weapons.
M21 Sniper Rifle
The M21, M24 and M40 sniper rifles of the US armed services and their derivatives have been with us since the Vietnam War. The M21 is built on the semi-automatic M14 action, while M24 and the Marines M40 are built upon Remington’s Model 700 action. The Army’s M24 is built on a long action 700 to accommodate change to 300 Winchester Magnum chambering and re-barreling. The Marine’s M40 is a short action limited to 308 Winchester length cartridges. Not many militaries are equipped with anything else, but times are changing. The M110 is based on the AR-10 and is a DM rifle more than a sniper, but holds under 1 MOA and chambered for the 7.62 NATO round.
Ma Deuce 50 Cal Machine Gun
Back during the Vietnam war a ‘Ma Deuce’ M2 .50 caliber heavy machine gun was equipped with a scope. The M2 can be fired not only in full auto, but semi-auto as well. These were used to interdict NVA and Viet Cong movement at night as the optics included night vision equipment. Move forward and we have Barret Arms supplying semi-auto and bolt action anti-material rifles chambered for .50 BMG (Browning Machine Gun). And a similar movement in eastern armies has been noted for the Russian 12.7x108mm cartridge. All though designed and designated as anti-material rifle these weapons have reached out and touched enemy soldiers out to a mile and half, a long ways.
.338 Lapua Magnum
But the newest phenomenon is the introduction of .338 Lapua Magnum. The extended ranges encountered in the middle east conflicts have mandated a rifle that can extend their effect ranges beyond 1000 yards. Some shots made have been truly phenomenal. The current record was by a Canadian using a McMillan Tac-50 in .50 BMG at 3,871 yards. A .338 Lapua Magnum holds the second- best record at 2,707 yards.
Other Sniper Cartridges
Another couple of cartridges that are entering some limited use is the Barret 416. It is a .50 BMG necked down to .416 caliber. The other interesting number is the Chey Tac M200 Intervention chambered in either .408 Chey Tac or .375 Chey Tac. These are based on the .505 Gibbs case and designed for 2500+ yard shooting. The 338 and .50 BMG based weapons are found in nearly every western national army’s arsenal. Long range interdiction of thin-skinned vehicles and personnel the purpose of these .50 caliber rifles. These fortyish based smaller bore weapons retain more energy beyond 2,000 yards than the .50 BMG. Rumor has it that the Army is re-barreling their M24 to 300 Winchester Magnum, extending their ‘touch’. A lot of fascinating stuff in the combat precision shooting arena.