300 Win Mag Ammo

.300 Winchester Magnum Ammo

The .300 Winchester Magnum (.300 Win Mag) ammo is a belted, bottlenecked magnum rifle cartridge ammunition that fires .30 caliber (7.62 mm) bullets weighing 150 to 220 grains (9.7 to 14.3 grams or g) at muzzle velocities of 2,850 to 3,300 feet per second (ft/s) or 869 to 1,006 meters per second (m/s), producing 3,628 to 4,100 foot-pounds of force (ft-lbf) or 4,919 to 5,600 joules (J) of muzzle energy. Winchester Repeating Arms Company introduced the .300 Win Mag cartridge in 1963, and the .300 Win Mag remains the most popular .30 caliber magnum ammunition in North America with factory loads from 12 manufacturers including Winchester, Remington, Federal, Hornady, Nosler, Barnes, Berger, Sierra, Lapua, Norma, Black Hills, and Sig Sauer. There are 4 categories of .300 Win Mag ammo: hunting ammunition with controlled-expansion bullets for big game, match-grade ammunition with Hollow Point Boat Tail (HPBT) bullets for long-range precision shooting, military-specification ammunition for sniper applications, and reduced-recoil ammunition for practice and smaller-framed shooters. This guide covers .300 Win Mag ammo by bullet weight and type, hunting loads for elk and deer, match loads for competition, cartridge dimensions and specifications, ballistic comparisons with the .308 Winchester and .30-06 Springfield, and related .300 Win Mag rifles and rifle scopes for long-range shooting.

Cartridge History

Winchester Repeating Arms Company developed the .300 Win Mag in 1963 by modifying the .338 Winchester Magnum case — moving the shoulder forward by 4.0 millimeters (mm) or 0.156 inches (in) and lengthening the case by 3.0 mm (0.120 in) to create a .30 caliber magnum that fits a standard-length rifle action. The .300 Win Mag parent case is the .375 Holland & Holland (H&H) Magnum, blown out and shortened. Before 1963, .30 caliber magnum options included the .30 Newton (1913), the .300 H&H Magnum (1925), and the .300 Weatherby Magnum (1944) — the .30 Newton failed commercially, the .300 H&H required a long action, and the .300 Weatherby used proprietary Weatherby rifles. The .300 Win Mag offered comparable performance in standard-length actions from Winchester (Model 70), Remington (Model 700), Ruger (M77), and Weatherby (Mark V), which drove rapid adoption. Newer .30 caliber magnums including the .300 Remington Ultra Magnum, .30 Nosler, .300 Norma Magnum, and .300 Precision Rifle Cartridge (PRC) have not matched the .300 Win Mag in ammunition sales or rifle chambering availability.

Design and Specifications

The .300 Win Mag ammunition uses a belted, bottlenecked case with a bullet diameter of .308 in (7.82 mm), case length of 2.62 in (66.5 mm), overall cartridge length of 3.34 in (84.84 mm), and a Large Rifle Magnum primer. The Sporting Arms and Ammunition Manufacturers' Institute (SAAMI) maximum average pressure is 64,000 pounds per square inch (psi) or 440 megapascals (MPa). The Commission Internationale Permanente pour l'Epreuve des Armes a Feu Portatives (C.I.P.) maximum pressure is 62,366 psi (430 MPa). The case capacity varies by manufacturer: Remington 88.0 grains of water (5.70 milliliters or ml), Federal 92.0 grains (5.96 ml), Winchester 93.8 grains (6.08 ml), and Norma 95.5 grains (6.19 ml). The recommended rifling twist rate is 1:10 in (254 mm) with 6 grooves.

Cartridge Dimensions

The .300 Win Mag cartridge dimensions per SAAMI specifications are:

• Bullet diameter: .308 in (7.82 mm), with a recommended projectile diameter of .309 in (7.85 mm)
• Neck diameter: .339 in (8.61 mm)
• Shoulder diameter: .489 in (12.42 mm)
• Base diameter: .513 in (13.03 mm)
• Rim diameter: .532 in (13.51 mm)
• Rim thickness: .050 in (1.27 mm)
• Case length: 2.62 in (66.55 mm)
• Overall length: 3.34 in (84.84 mm)
• Case capacity: 91.5 grains of water (5.93 ml) per SAAMI specification

The SAAMI bore diameter is 7.62 mm (0.300 in) with a groove diameter of 7.82 mm (0.308 in). C.I.P.-regulated countries proof-test .300 Win Mag rifles at 125% of maximum pressure — 537.50 MPa (77,958 psi) — before certifying the firearms for sale.

Performance

150-Grain Bullets

The 150 grain (9.7 g) .300 Win Mag bullet reaches muzzle velocities of 3,260 to 3,300 ft/s (994 to 1,006 m/s) in factory loads and up to 3,400 ft/s (1,036 m/s) in older Winchester "Power Point" soft point loads, with a maximum point blank range of 291 meters (318 yards or yd) when zeroed at 250 m (273 yd). The 150 grain bullet has a lower ballistic coefficient than heavier options but compensates with the flattest trajectory in the .300 Win Mag bullet weight range. The 150 grain weight is suited for light-skinned big game including white-tailed deer, mule deer, and bighorn sheep at distances beyond 300 yards (274 m).

165-Grain Bullets

The 165 grain (10.7 g) .300 Win Mag bullet reaches a muzzle velocity of approximately 3,160 ft/s (963 m/s), which is 100 to 150 ft/s slower than the 150 grain bullet while offering a higher ballistic coefficient for better wind resistance and energy retention at range. The 168 grain variant is popular among .300 Win Mag and other .30 caliber magnum cartridge shooters. The 165 to 168 grain range provides the best balance between flat trajectory and terminal performance for hunters who want a single load for deer and elk.

180-Grain Bullets

The 180 grain (11.7 g) bullet is the most popular .300 Win Mag bullet weight, with a muzzle velocity of 2,950 to 3,193 ft/s (899 to 973 m/s) from factory loads and a high ballistic coefficient that retains energy at long range for taking big game of any weight class in North America. The 180 and 185 grain bullets are the most versatile .300 Win Mag options, offering enough penetration for elk and moose with controlled-expansion designs while maintaining a flat trajectory for shots beyond 300 yards. Remington loads the Core-Lokt 180 grain Pointed Soft Point (PSP) at 2,960 ft/s, the Core-Lokt Tipped 180 grain at 2,980 ft/s, the Premier Scirocco 180 grain Swift Scirocco Bonded at 2,960 ft/s, the Core-Lokt Copper 180 grain Copper Hollow Point (HP) at 2,850 ft/s, and the Premier CuT 180 grain Copper Tipped at 2,960 ft/s.

190 to 220-Grain Bullets

Heavy bullets from 190 to 220 grains (12.3 to 14.3 g) provide the highest ballistic coefficients in the .300 Win Mag lineup, with muzzle velocities of 2,700 to 3,117 ft/s (823 to 950 m/s) and superior wind deflection resistance at distances beyond 600 yards (549 m). Long-range competition shooters prefer 190 to 220 grain bullets for 1,000-yard (914 m) matches. Remington loads the Premier Long Range 190 grain Speer Impact at 2,885 ft/s. The military MK 248 MOD 1 uses a 220 grain (14.26 g) Sierra MatchKing HPBT at 2,850 ft/s (869 m/s) nominal velocity with Hodgdon H1000 propellant, achieving a maximum effective range of 1,500 yards (1,372 m). Heavy bullets seated to magazine length in the .300 Win Mag case reduce internal powder volume because the overall cartridge length is limited to 3.34 in (84.84 mm) by the C.I.P. standard.

Comparison with Other .30 Caliber Big Game Cartridges

The .300 Win Mag produces 3,992 ft-lbf (5,412 J) of muzzle energy with a 180 grain bullet at 3,160 ft/s, compared to 2,872 ft-lbf (3,894 J) for the .30-06 Springfield with a 165 grain bullet at 2,800 ft/s, and 2,658 ft-lbf (3,604 J) for the .308 Winchester with a 150 grain bullet at 2,825 ft/s. At 500 yards (457 m), the .300 Win Mag retains 2,187 ft-lbf (2,965 J) while the .30-06 retains 1,281 ft-lbf (1,737 J) and the .308 Winchester retains 1,166 ft-lbf (1,581 J). The .300 Weatherby Magnum with a 180 grain bullet at 3,250 ft/s produces 4,223 ft-lbf (5,726 J) at the muzzle — 6% more than the .300 Win Mag — but requires a long magnum action and costs more per round. The .300 Win Mag provides approximately 400 ft/s (122 m/s) more velocity and 20% more energy than the .30-06 Springfield at all distances.

The .300 Win Mag recoil energy is approximately 30 ft-lbf — 30% greater than the .30-06 Springfield. The recoil is manageable with muzzle brakes that reduce felt recoil by 30% to 50%. Remington produces Managed-Recoil .300 Win Mag ammunition that reduces recoil to .30-06 levels while providing .30-06-equivalent performance.

Hunting Applications

The .300 Win Mag ammo serves big game hunting worldwide with factory ammunition loaded with controlled-expansion bullets from 150 to 200 grains for game ranging from white-tailed deer to moose. Hunting ammunition by bullet weight and game class:

• 150 grain soft point and ballistic tip: medium-sized game (white-tailed deer, mule deer, pronghorn) at distances to 400 yards (366 m)
• 165 to 168 grain bonded and partition: medium to large game (mule deer, caribou, black bear) at distances to 500 yards (457 m)
• 180 grain controlled-expansion (Nosler Partition, Swift Scirocco, Remington Core-Lokt): all North American big game including elk up to 450 kg (992 lb) and moose up to 640 kg (1,411 lb) at distances to 400 yards
• 200 grain bonded and monolithic: heavy-boned game (elk, moose, grizzly bear, African plains game) at distances to 300 yards (274 m)

The .300 Win Mag is effective on dangerous game including black bears and grizzly bears with heavy bonded bullets. African plains game hunters use the .300 Win Mag for animals up to eland size. Mountain hunters choose the .300 Win Mag for bighorn sheep and Dall sheep hunting because the flat trajectory and energy retention allow clean kills at 300 to 600 yards in open mountain terrain.

Military and Law Enforcement Applications

The .300 Win Mag serves as a long-range sniper cartridge adopted by the United States (U.S.) military, North Atlantic Treaty Organization (NATO) allies, and law enforcement specialist units for engagements beyond .308 Winchester range. The maximum effective range with standard .300 Win Mag sniper ammunition is 1,210 yards (1,107 m), extending to 1,500 yards (1,372 m) with MK 248 MOD 1 ammunition. Sub-1 Minute of Angle (MOA) accuracy at 1,000 yards (914 m) is standard in precision-built rifles firing match-grade ammunition.

Military and Law Enforcement Firearms

Military and law enforcement sniper rifles chambered in .300 Win Mag include:

• United States: M2010 Enhanced Sniper Rifle (ESR), M24 Sniper Weapon System (SWS), MK 13 rifle, Armalite Model AR-30, Remington Model 700 Police Long Action, Savage Model 110BA, Weatherby Threat Response Rifle (TRR)
• Finland: Sako TRG-42
• Germany: Bundeswehr G22
• United Kingdom: Accuracy International Arctic Warfare Magnum (AWM)

Ammunition Options

The .300 Win Mag ammo is available in 3 bullet style categories, 5 common grain weights, and 3 primary use cases from major ammunition manufacturers.

Bullet Styles

• Soft Point (SP) and Pointed Soft Point (PSP): exposed lead tip for controlled expansion on game — Remington Core-Lokt PSP 180 grain at 2,960 ft/s is the best-selling .300 Win Mag hunting load
• Bonded and Tipped: polymer tip over a bonded lead core that retains 80% to 95% of original weight for deep penetration — Swift Scirocco, Nosler AccuBond, Remington Core-Lokt Tipped, and Hornady Superformance Super Shock Tip (SST)
• Monolithic copper and copper alloy: lead-free expanding bullets for areas with lead ammunition restrictions — Barnes Tipped Triple-Shock (TTSX), Hornady Gilding Metal eXpanding (GMX), and Remington Core-Lokt Copper Hollow Point
• Hollow Point Boat Tail (HPBT): match-grade bullets for long-range precision — Sierra MatchKing 190 and 220 grain, Berger Hybrid 215 and 230 grain

Featured Ammunition

Remington produces 7 .300 Win Mag ammunition loads across hunting, long-range, and lead-free categories:

• Core-Lokt 180 grain Pointed Soft Point Core-Lokt at 2,960 ft/s: the traditional hunting load with controlled expansion for deer and elk
• Premier Long Range 190 grain Speer Impact at 2,885 ft/s: a high-ballistic-coefficient bonded bullet for hunting at extended range
• Core-Lokt Tipped 180 grain Core-Lokt Tipped at 2,980 ft/s: polymer-tipped version of the Core-Lokt with a higher ballistic coefficient and faster expansion initiation
• Premier Scirocco 180 grain Swift Scirocco Bonded at 2,960 ft/s: a premium bonded bullet that retains 90%+ weight for deep penetration on elk and moose
• Core-Lokt Copper 180 grain Copper HP at 2,850 ft/s: a lead-free solid copper expanding bullet for states and countries with lead ammunition bans
• Core-Lokt 150 grain Pointed Soft Point Core-Lokt at 3,290 ft/s: a flat-shooting load for deer and sheep at long range
• Premier CuT 180 grain Copper Tipped at 2,960 ft/s: a premium copper-tipped hunting bullet with a polymer tip for rapid expansion

Handloading Components

Handloaders assemble .300 Win Mag ammunition using 4 components: brass cases, Large Rifle Magnum primers (Federal 215 Match or CCI 250), slow-burning powders (H1000, Retumbo, Vihtavuori N565, Vihtavuori N570), and .308 caliber bullets from 150 to 230 grains. Handloading the .300 Win Mag offers 3 advantages over factory ammunition: optimized loads tailored to specific rifles for sub-MOA accuracy, reduced cost per round after the initial equipment investment, and access to bullet designs not available in factory loads. The .300 Win Mag short neck requires careful attention to bullet seating depth, neck tension, and case concentricity to maintain accuracy. Case capacity varies across brass manufacturers by up to 7.5 grains of water, which requires adjusting powder charges when switching between Remington, Federal, Winchester, and Norma brass.