MK 248 MOD 1 .300 Magnum Cartridge

The MK 248 MOD 1 cartridge is for use in the Remington 700 family of weapons (bolt action only) chambered for .300 Winchester Magnum cartridges. Winchester® Supreme® Centerfire Rifle Ammunition stands as the most technologically advanced line of centerfire rifle ammunition in history. In 1873, less than a decade after the Civil War and when Westward expansion was in full gallop, Winchester introduced the first successful centerfire cartridge: the .44 WCF (.44-40). Designed for double duty in both rifles and handguns, this is the cartridge that won the west. And to hunters and sportsmen wanting the ultimate ammunition for any big-game need, Winchester has been delivering ever since.

• Since 1960, more Whitetail deer have been taken with Winchester® Power-Point® ammunition than any other bullet Winchester has produced. The Power-Point bullet was specifically designed for excellent knock-down performance with an exposed soft lead-alloy nose and strategically notched metal jacket that controls bullet expansion for a crushing energy release.
• The 300 Winchester Magnum 180 Gr. Supreme® AccubondT Ct® features delayed, controlled expansion. Deep penetration through thick, tough skin, heavy muscle tissue and bone, high retained weight
• The 300 Winchester Magnum Ballistic Silvertip® features a solid based boat tail design that delivers excellent long range accuracy. In medium to larger calibers special jacket contours extend range and reduce cross-wind drift. Harder lead core ensures proper bullet expansion.
• The 300 Winchester Magnum 180 Gr. Supreme® E-tip features delayed, controlled expansion. Deep penetration through thick, tough skin, heavy muscle tissue and bone, high retained weight
• The new XP3® bullet starts with a 2-stage expansion design, then combines all the best-known bullet technology into one bullet. It delivers precision accuracy, awesome knockdown power, and deep penetration all in one package -- and it's as effective on thin-skinned game, like deer and antelope, as it is on tough game, like elk, moose, bear, and African animals, at short and long ranges. The XP3® is the closest thing to a perfect hunting bullet.

MK 248 MOD 1 cartridge components are the projectile, the cartridge case, the propellant, and the primer. The projectile for the MK 248 MOD 1 is the 220 grain Sierra MatchKing Hollow Point Boat Tail (HPBT) bullet, commercial part number 2240, manufactured by Sierra Bullets. The bullet has a lead or lead alloy core and copper or copper alloy jacket. The bullet has a nominal weight of 220 grains, with a tolerance of 0.5 grains. The bullet diameter is 0.3086-0.0005 inches. The bullet is of the reverse drawn, Open Tip Match (OTM) type capable of meeting the accuracy requirements. The cartridge case is the .300 Winchester Magnum constructed of copper alloy in accordance with ASTM B19, and is not plated. The cartridge case meets the external dimensional requirements of ANSI/SAAMI Z299.4-1992. A venthole is present in the primer pocket of the cartridge case. The cartridge case head stamp marking consists of the identification code of the manufacturer, last 2 digits of year of manufacture and the notation "300 WM" or "300 WINMAG".

The primer is a large match rifle primer, non-corrosive, nickel-plated, boxer type, and is of lead-styphnate type. The primer has a brass anvil and brass cup. The primer is capable of meeting the ballistic requirements. Each cartridge contains Hodgdon H1000 propellant. The propellant loaded in this cartridge contains flash reduction additives or coatings, and meets temperature stability and ballistic requirements. The primer is seated in the cartridge case to a depth of 0.000 to 0.008 inch below theface of the cartridge case head. The primer is not staked or crimped in place.

The nominal overall length of the assembled cartridge is 3.500 inches maximum and 3.450 inches minimum. The distance from the cartridge case head to the 0.300 inch diameter datum on the projectile ogive is controlled to within 0.010 inches. The nominal overall length and the distance from the cartridge case head to the 0.300 inch diameter datum on the projectile ogive of the assembled cartridge is established, within these limits, by the manufacturer to meet performance requirements. The cartridge headspace is 0.212 inches minimum, 0.220 inches maximum. Cartridge headspace is measured from the base of the cartridge case to the opposite surface of the beltof the cartridge case.

The corrected average muzzle velocity of the cartridges conditioned at 70° +/- 5° Fahrenheit (F) is 2,850 +/- 50 ft/sec. feet per second (fps)]. The standard deviation of the corrected muzzle velocity at 70° +/- 5° F does not exceed 15fps. The corrected average chamberpressure does not exceed 68,100 pounds per square inch (psi) at 70°F. Neither the chamber pressure of an individual sample test cartridge nor the average chamber pressure plus three standard deviations of chamber pressure exceeds 78,900 psi.

The extreme spread of any individual 10-shot group does not exceed 4.5 inches at 300 yards. The average extreme spread of ten, 10-shot groups does not exceed 3.5 inches at 300 yards. The extreme spread of any individual 10-shot group does not exceed 9.0 inches at 600 yards. The average extreme spread of ten, 10-shot groups does not exceed 7.0 inches at 600 yards.