Medium Bore All-Around Rifle Cartridges
By Chuck Hawks
The cartridges with reasonable claim to being "all-around" big game (Class2/Class 3) hunting cartridges typically range from caliber .26 (6.5mm) to caliber .32 (8mm). Basically, these are small bore cartridges that start with the standard 6.5mm cartridges (6.5x55 SE, .260 Rem., etc.) and end with the .300 Magnums and 8x68S.
At least in North America, the most popular all-around hunting cartridges are the .270, 7mm and .30 calibers. The cartridges that made the "short list" in my article All Around Rifle Cartridges were the .270 Winchester, 7mm Remington Magnum, .308 Winchester and .30-06 Springfield.
These four cartridges were the only ones to meet all of the criteria for an ideal all-around cartridge: adequate bullet diameter and sectional density, a maximum point blank range (+/- 3 inches) of at least 250 yards with typical factory loads, recoil not exceeding 20 ft. lbs. in rifles of typical weight, a good selection of widely available factory loaded ammunition and reloading components, and offered in a large number of rifles. Keep in mind that an all-around rifle will probably be carried a lot and fired a lot.
Of course, in special circumstances, there are potential choices beyond the small bore cartridges considered in the article. Where Class 3 game predominates, where game is hunted almost entirely in terrain where shots are taken at short to medium range (225 yards or less), where the bullet may be called upon to "buck brush," or where a chance encounter with a dangerous predator (bear or big cat) is entirely possible, a medium bore cartridge that can reasonably be chambered in a medium weight rifle (8.0-8.5 pounds) might deserve serious consideration for all-around use.
Standard velocity medium bore cartridges, such as the .338 Marlin Express, .338 Federal, .338-06 A-Square, .348 Winchester, .358 Winchester, .35 Whelen and 9.3x62mm immediately come to mind. Medium bore magnums, such as the .338 Win. Mag. and .375 H&H Mag., can offer superior ballistics, but kick much too hard for consideration here.
Of course, none of these standard medium bore cartridges are particularly popular in North America, Australia, South America and Asia. In most places, ammunition and rifles are not nearly as widely available as for the four small bore, short list cartridges. (In Europe and sub-Saharan Africa, however, the 9.3x62mm remains a popular cartridge.)
Among these standard medium bores, the relatively new .338 Federal and the classic 9.3x62mm are probably offered in the most rifles and with the widest range of factory loads, while the .338-06 offers the flattest trajectory (comparable to many small bore all-around cartridges) with normal hunting weight bullets. The latter is, unfortunately, really suitable only for reloaders, as factory loaded ammunition is scarce to nonexistent.
There is certainly nothing wrong with choosing a medium bore cartridge as your all-around favorite. Ballistically, the .338-06 would serve admirably in areas where Class 3 game predominates, but the occasional deer or other Class 2 animal is taken.
The biggest problem is recoil. To maintain equivalent SD (.261-.271) and BC to a 140 grain .270, 150 grain 7mm or 180 grain .30 bullet, a .338 bullet must weigh at least 210 grains (SD .263). Launch that heavier bullet at the same velocity (2700 fps) to achieve the same trajectory as one of the small bore favorites, which takes a maximum powder charge in the .338-06, and the recoil in an all-around rifle becomes heavier than most shooters can handle without flinching.
Some North American shooters consider the 8mm cartridges to be semi-medium bores, but a similar problem afflicts the powerful 8mm cartridges, albeit to a somewhat lesser extent. It takes a 200 grain 8mm bullet to equal the SD and BC of a 180 grain .30 bullet. If you launch that heavier bullet at the same 2700 fps velocity, a maximum load in the 8x57JS or 8mm-06, the kick is above the 20 ft. lb recoil energy maximum most shooters can (or will) tolerate. The standard 180 grain .30-06 load is right at 20 ft. lbs. of recoil in an eight pound hunting rifle.
I am convinced this is one of the reasons 8mm cartridges have never been popular in North America. In Europe, where there are few Class 3 animals (except in Scandinavia), the popular 8x57 Mauser is mostly used with 150 grain bullets (SD .205).
The same applies to the standard medium bore cartridges, only more so. You can reduce the recoil by reducing the bullet weight, but this defeats the purpose of using a medium bore cartridge in the first place.
For those who can tolerate the elevated recoil and achieve consistent, precise bullet placement and can live with the limited availability of rifles and factory loaded ammunition, the standard medium bore cartridges offer a practical alternative to the small bore all-around cartridges. For many hunters in places such as Alaska, Canada and sub-Saharan Africa a medium bore rifle is their all-around choice.
Copyright 2016 by Chuck Hawks.com. All rights reserved.