.300 Winchester Magnum
The .300 Winchester Magnum also referred to as the '300 Win Mag' introduced by Winchester in 1963 remains one of the most popular magnum rifle cartridges of all time.
The .300 Winchester Magnum is in fact based on the .375 H&H Magnum, which has been blown out, shortened, and necked down to accept a .30 caliber (7.62 mm) bullet and was designed to fit in any standard action rifle.
(Left: The 300 Win Mag)
It is an extremely versatile calibre and has been adopted by target shooters, law enforcement agencies and the military. Hunters have also found the cartridge to be highly effective for everything up to dangerous game and it remains highly popular in both the U.S and in Africa for plains game.
If you stalk in the UK and fancy it, well good luck...it's not un heard of to be granted an FAC for this calibre, however on the whole the Police in the UK consider this calibre to be a little over the top if it is purely UK deer that you are after. Suffice to say I have heard of a few individuals being granted a slot for a 300 Win Mag in the UK, one of whom required a powerful calibre for the management of large lowland Red deer. This however is the exception not the rule.
If on the other hand your deer hunting also involves trips abroad to Europe, Africa and the US, then this is truly one of the all time great calibres, fast, flat and powerful!
That said, on the ballistic's front, today the 300 Win Mag has in fact been surpassed in performance by the more powerful .300 Weatherby Magnum and the newer .300 Remington Ultra Magnum. However it's iconic and long standing reputation around the world and wide availability of ammunition, means that it remains a highly popular calibre and will, I suspect, remain so for some considerable time to come.
Performance is impressive, you can typically expect a 180 grain bullet to be driven at over 3000fps creating nearly 4000 ftlbs of energy at the muzzle and retaining 2500 ft lbs at 300 yards. Drop at 300 yards with a 200 yard zero is as little as 6 inches.
Typical Ballistics: (180 grain bullet)
Muzzle Energy: 4000 ft/lbs
Muzzle Velocity: 3000 fps