By John McAdams
300 Win Mag vs 7mm Mag
Most hunters probably agree that the 7mm Remington Magnum and .300 Winchester Magnum are both fantastic choices for hunting a wide variety of big game, including bear. They’re both calibers able to handle the longer range shooting of hunting the big ungulates, but also the big body structure of bruins. However, many people get confused about the pros and cons of the two cartridges.
The 300 Win Mag on the left, and the 7mm Mag is on the right. They're both flat shooting, hard hitting and very accurate cartridges for bear.
In this article, I’m going to detail the history of the cartridges as well as their strengths and weaknesses in order to provide you with the necessary information to decide which you should use in various hunting situations.
Remington changed the shooting world forever in 1962 when they introduced the Remington Model 700 rifle along with the 7mm Remington Magnum. Using a shortened .375 H&H Magnum case paired with a .284" bullet, the 7mm Remington Magnum offered a significant ballistic improvement over most other popular cartridges of the day like the .30-06 Springfield.
Additionally, the new 7mm Remington Magnum cartridge fit in a standard length rifle action. This meant it could be used in many of the same rifle models popular among hunters during that time period chambered in cartridges like the .270 Winchester and .30-06 Springfield. With all that in mind, it's not surprising at all that the flat shooting and hard-hitting 7mm Rem Mag quickly caught on with hunters in North America.
Designers at Winchester during that timeframe could see what direction the wind was blowing and they began work on a .30 caliber magnum cartridge using the case from the .338 Winchester Magnum (itself descended from the .375 H&H) as a model. The company formally introduced the fruits of their labor to the world in 1963 as the .300 Winchester Magnum.
Like the 7mm Mag, the .300 Win Mag had a significant ballistic advantage over cartridges like the .30-06 and also fit in a standard length rifle action. For those reasons, the .300 Win Mag was also an instant hit with American hunters.
You can see some of the differences between the .300 Winchester Magnum and 7mm Remington Magnum in the photos. The .300 Win Mag has a slightly greater overall length (3.34" vs 3.29"), but both cartridges are used in standard (instead of magnum) length action rifles. The .300 Winchester Magnum has a slightly longer case length (2.62″ vs 2.5″) as well as a shoulder that sits .156" further forward than the shoulder of the 7mm Rem Mag. Though they both have the same rim diameter and are very similar in overall length, the .300 Win Mag has a 5-8% advantage in capacity over the 7mm Rem Mag due to its shoulder placement and longer case length.
As you'd expect from the fact that the two cartridges are very close in overall size, the ballistics of the 7mm Rem Mag and .300 Win Mag are also pretty similar.
The biggest difference between them is the size and weight of the bullets they fire. The 7mm Remington Magnum uses .284" bullets and the .300 Winchester Magnum uses .308" bullets.
Everything else being equal, the smaller diameter 7mm bullets have a higher ballistic coefficient and a higher sectional density than the larger diameter bullets of the same weight from the .300 Winchester Magnum. However, the .300 Winchester Magnum generally uses heavier bullets than the 7mm Remington Magnum.
For instance, the vast majority of 7mm Rem Mag loads shoot bullets in the 139-175 grain range. On the other hand, most .300 Win Mag loads use 150-230 grain bullets.
As you can see in the table below comparing 150gr Barnes TTSX and 168gr Nosler AccuBond Long Range loads in 7mm Remington Magnum to 165gr Barnes TTSX and 190gr Nosler AccuBond Long Range loads in .300 Win Mag, the .300 Win Mag has a small edge, but there isn't a gigantic difference in the ballistics of the cartridges.
The .300 Win Mag has slightly less bullet drop and carries more energy down range. This is due in large part to the fact that the cartridge uses heavier bullets and has more case capacity. However, since the 7mm Mag bullets compared above have a slightly higher ballistic coefficient, the gap in kinetic energy between the two bullets closes slightly at longer ranges.
The table below shows how a 10mph crosswind impacts those same loads out to 500 yards. As you can see, the Barnes loads have a nearly identical amount of wind drift, but the 7mm Rem Mag has a slight edge over the .300 Win Mag with the AccuBond loads. For all practical purposes, there isn't a significant difference in the ballistics of the .300 Win Mag and 7mm Rem Mag at typical hunting ranges. They’re flat shooting, hard hitting, and very accurate cartridges.
That being said, the .300 Win Mag has more recoil than the 7mm Rem Mag. For example, when fired from the exact same rifle, a .300 Win Mag load firing a 165 grain bullet has about 25% more recoil than a 7mm Rem Mag load firing a 150 grain bullet at a similar muzzle velocity.
The .300 Win Mag and 7mm Rem Mag are both extremely popular magnum cartridges and consistently rank among the best-selling rifle cartridges in the USA each year. For that reason, virtually every ammunition manufacturer of note produces a wide array of high quality factory ammunition in nearly every major bullet model for both cartridges.
Along with lots of choices for ammunition, there are many great hunting rifles produced by nearly every firearms manufacturer chambered in 7mm Remington Magnum and .300 Winchester Magnum. Additionally, because the cartridges are the same length and have the same rim diameter, rifles of the same model chambered in each cartridge are virtually identical.
The vast majority of 7mm Mag loads shoot bullets in the 139-175 grain range. Most .300 Win Mag loads use 150-300 grain bullets.
When using quality bullets and with good shot placement, both the 7mm Rem Mag and .300 Win Mag are excellent for hunting black, brown, and grizzly bear at all practical hunting ranges. However, since they are such flat shooting and hard hitting cartridges, the 7mm Mag and .300 Win Mag really shine in situations where hunters need to take shots out past 200-300 yards.
The smaller caliber 7mm Remington Magnum is wonderful for smaller and lighter animals. By the same token, the lighter recoil of the cartridge also makes the 7mm Mag a great choice for smaller framed or recoil shy hunters. It’s also ideal for situations where a lightweight rifle is really desirable, like on a backpack or mountain hunt.
On the other hand, since it shoots heavier and larger diameter bullets, the .300 Win Mag has a clear advantage when hunting larger, tougher, and more dangerous game.
Don't get me wrong, you can absolutely hunt species like grizzly bear with the 7mm Rem Mag and untold numbers of hunters have successfully used it in that role over the years. There’s also nothing saying the .300 Win Mag isn’t suitable for smaller animals or that it isn’t appropriate for a mountain hunt.
Like I said earlier, the 7mm Remington Magnum and .300 Winchester Magnum are both quite versatile, but each cartridge is just a better choice for certain applications. The fact that I have to nitpick the strengths and weakness of each cartridge like that really speaks to their overall effectiveness. All that being said, the difference between them isn't as great as it is sometimes made out to be and the animal will never know the difference if your shot is placed correctly.
This article was first published by John McAdams on The Big Game Hunting Blog and is reprinted here with slight modifications for length with his permission.