300 Win Mag

Using the 375 H&H parent cartridge, complete with belt, the 300 win mag was shortened down to fit into normal action lengths and blown out to get more capacity.  The result is a cartridge that fires a 180gr projectile the same speed a 30-06 fires a 150gr projectile and fits into the same action.

The .375 H&H family From left to right: .308 Winchester, 7mm Remington Magnum, .300 Winchester Magnum, .338 Winchester Magnum, .375 Holland and Holland Magnum, .450 Marlin

Since 1963 the 300 win mag cartridge has had great success in both the recreational market as well as Military applications.  The famous sniper Chris Kyle said that the 300 win mag platform that he used was his favourite by far.

The cartridge has a .532” diameter belt and rim and is 2.620” long – approximately 3mm longer than the 30-06.  Due to this this cartridge suffers from having a short neck and throat relative to other 30 calibre cartridges, but this is overshadowed by its considerable powder capacity.

From left to right: .308 Winchester, .30-06 Springfield, .300 Winchester Magnum, .300 WSM

Most 300 Win Mag rifles come from the factory with barrels that have 1/10” twist rifling.  This allows for the use of light projectiles, such as 125gr Nosler Ballistic Tip and 130gr Speer hollow point projectiles; heavy projectiles such as the Berger or Nosler 210gr hollow point and most projectiles in-between.  These heavy, match grade projectiles are really what makes a 300 win mag shine – firing these heavy projectiles the 300 win mag has almost 2 meters less drop, half a meter less wind and is supersonic 280 meters further than a 338 Lapua firing a 250 grain Sierra Match King to the transonic zone.

From left to right: .300 Winchester Magnum, .338 Lapua Magnum

Many rifles are manufactured in 300 win mag – light sporting and carry rifles; varmint rifles; tactical rifles and target rifles.  This is a testament to the versatility of this cartridge.  The rifle pictured is a Sako TRG 42 in 300 win mag.