7x57mm Mauser, 7mm-08 Rem, 6.5x55 SE and .260 Rem:
By the Guns and Shooting Online Staff
Any evaluation of a general purpose big game hunting cartridge should account for several, diverse factors. These include (in no particular order) killing power (including bullet sectional density), recoil (less than 20 ft. lbs.), trajectory (minimum 250 yard MPBR), practical accuracy, the availability of reloading components, rifles and factory loaded ammunition locally and worldwide. In the popular and definitive Guns and Shooting Online article "All-Around Rifle Cartridges," virtually all qualifying candidate cartridges were evaluated and the final "short list" of the best candidates devolved to four calibers: .270 Winchester, 7mm Rem. Mag., .308 Winchester and .30-06 Springfield. Only these four cartridges scored high in every category.
The 7x57, 7mm-08, 6.5x55 and .260 Rem. were included in that article, but could not match the four short list cartridges in the area of availability of rifles and ammunition (read popularity). However, for the reloader or someone who lives where factory loaded ammunition is readily available (this includes most medium size or larger towns in the U.S.), these four outstanding cartridges deserve serious consideration. This is especially true if you primary annual quarry is deer, feral hogs, sheep, goats, antelope and black bear, with CXP3 game (elk and critters of similar size) only an occasional or theoretical consideration.
The 7x57 and 6.5x55 are among the world's classic hunting cartridges, proven on all manner of game, from tiny European chamois to Scandinavian moose, arctic polar bear and all African CXP2 and CXP3 plains game. These and similar, but less well known, cartridges have even brought down more than their fair share of the African Big Four dangerous species, mostly in the hands of local farmers and professional hunters.
The .260 Remington (originally known as the 6.5mm-08) is the ballistic twin of the 6.5x55, but based on a necked-down .308 Winchester case. The 7mm-08 is the ballistic twin of the 7x57, but based on a necked-down .308 case. Loaded to the same pressure, there is virtually no difference in ballistics between the classic and .308 based cartridges. The advantage of the latter is simply that they are sized to neatly fit in modern short action rifles, while the 7x57 and 6.5x55 are intermediate length cartridges; that is, between the .308 and .30-06 in cartridge overall length (COL). However, the longer (metric) cases have longer necks, which means that very heavy for caliber bullets do not intrude deep into the powder space. (The 7x57 was designed for 175 grain bullets and the 6.5x55 for 160 grain bullets.) If hunting CXP2 game is your primary consideration, these four are exemplary cartridges, regardless of COL.
The 7x57, 7mm-08, 6.5x55 and .260 can handle bullets ranging from about 100-160 grains very effectively. (In the case of the 7x57, also 175 grain bullets.) Bullets weighing about 140 grains are the all-around big game hunting bullets and the most popular choice. These are generally driven at a muzzle velocity (MV) of about 2700 fps in full power hunting loads. A 140 grain 6.5mm (.264" diameter) bullet has a SD of .287, while a 140 grain 7mm (.284" diameter) bullet has a SD of .248, which bodes well for penetration in both cases. For comparison, a 150 grain .308 bullet has a .226 SD.
Comparing our four calibers, the velocity and energy are about equal. Theoretically, the 7mm punches a slightly larger diameter hole with its fatter bullet and the 6.5mm punches a deeper hole due to its advantage in SD. No deer is going to be able to tell the difference, or live long enough to debate the issue. For those who are interested, there is a series of cartridge comparison articles on the Rifle Cartridges page that delve into ballistic comparisons and include all four of these cartridges.
The 7x57, 7mm-08, 6.5x55 and .260, collectively, are used by almost all of the Guns and Shooting Online staff. They are also popular with custom rifle makers and the (generally) very experienced hunters who order bespoke rifles. Why are they so popular among knowledgeable hunters? In a nutshell, because they get the job done with maximum effectiveness and minimum fuss. This is especially important for use in the lightweight hunting rifles that are the current fad. These cartridges kill about as well as a .270 or .280 and kick less, which makes accurate shot placement in the field easier. It is getting that first bullet into the animal's vitals that fills the freezer and these calibers help the hunter do just that.
Nor is there a great difference in trajectory between these more modest cartridges and the long action .270 Winchester and .280 Remington. According to the "Expanded Trajectory Table" (see the Tables, Charts and Lists page), with 140 grain bullets the larger cartridges have an advantage in MPBR (+/- 3") of about 20-25 yards, depending on the specific loads compared. Very seldom will that matter in the field.
The 6.5x55 and 7x57 are usually chambered in long (.30-06 length) actions, while the .260 and 7mm-08 are usually chambered in short (.308 length) actions. Those who obsess about the approximately ½" difference in action length will probably prefer the .260 or 7mm-08, while to everyone else the difference is not critical. Of course, many modern actions actually come in only one length (long); the manufacturer simply blocks the magazine and bolt travel to accommodate short action calibers. The receiver is actually the same length whether chambered for .308 or .30-06 length cartridges, so the theoretical advantage of a short action does not apply.
In Europe, the 7x57 and 6.5x55 are more popular and better established than the newer cartridges, so in most areas rifles and ammunition are probably more readily available for these classic calibers. (After all, these two are European calibers.) The 7x57 has long been popular in Africa and South America and there it would probably be the odds-on favorite in terms of the availability of rifles and ammunition. For hunting in North America and Australia, the choice between these four cartridges will probably come down to the preferred rifle. Not all calibers are available in all rifles, but one or another of our four contenders is available in most.
In conclusion, we hope that this little article has spurred your interest in these mild mannered, but highly effective, hunting cartridges. You will be doing yourself a favor if you try them.
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