Compared: The .260 Rem. and 6.5x55 SE
By Chuck Hawks
In Europe, 6.5mm (.264 caliber) cartridges are very popular, and many African, Australian, North and South American hunters have also discovered the low recoil and good killing power of 6.5mm rifles. Common 6.5mm cartridges range in size and killing power from the 6.5x50 Arisaka to the powerful .264 Winchester Magnum. About in the middle, and probably the most useful and versatile of the entire 6.5mm family, are the .260 Remington and 6.5x55 SE.
Among the readers of Guns and Shooting Online the articles on both the .260 Rem. and 6.5x55 SE cartridges get a lot of page views every month. Frankly, more than I had expected. Both place well up in the top 100 out of the 500 articles on chuckhawks.com that are tracked by Urchin Web Stats. (There are more than 500 articles and features on the entire chuckhawks.com WebSite, but Urchin only reports page views on the top 500.) There is evidently a substantial interest in both of these cartridges.
The .260 is basically just a newer version of the 6.5x55 based on a necked-down .308 Winchester case. It can be thought of as the American equivalent of the 6.5x55, as the ballistic capabilities of the two cartridges are nearly identical.
Like all .26 caliber/6.5mm cartridges, the .260 and 6.5x55 achieve their excellent killing power primarily due to the excellent sectional density (SD) of their hunting weight bullets. Standard .264" (6.5mm) diameter bullets have outstanding SD compared to bullets of similar weight, type and purpose in the popular .243, .257, .270, 7mm, and .30 calibers, which gives them the potential for superior penetration.
For those who are curious, here are the SD's for some common .264" bullet weights: 85 grain, SD = .174; 95 grain, SD = .195; 100 grain, SD = .205; 120 grain, SD = .246; 125 grain, SD = .256; 129 grain, SD = .264; 140 grain, SD = .287; 160 grain, SD = .328. Sectional density is probably the most valid way to compare bullets of different caliber.
Perhaps it would be useful to also include the SD's of some popular bullet weights in other calibers for comparison: 70 grain .243, SD = .169; 80 grain .243, SD = .194; 100 grain .243, SD = .242; 117 grain .257, SD = .253; 130 grain .270, SD = .242; 150 grain .270, SD = .279; 140 grain 7mm, SD = .248; 160 grain 7mm, SD = .283; 175 grain 7mm, SD = .310; 165 grain .308, SD = .248; 180 grain .308, SD = .271; 200 grain .308, SD = .301.
Perhaps these numbers help to explain how the .260 and 6.5x55 can challenge the .243 as a long range varmint cartridge on one hand and the larger .270, 7mm and .30 calibers as big game cartridges on the other. As these numbers show, the 85 and 95 grain .264" bullets are fine long range varmint medicine.
The 120 grain .264" bullet is equivalent to a 100 grain .243, 130 grain .270, 140 grain 7mm, or 165 grain .30 caliber bullet. These are all excellent CXP2 class game bullets.
The popular 140 grain .264" bullet is more than equal to the 150 grain .270, 160 grain 7mm, and 180 grain .30 caliber bullets. All are fine bullet weights for CXP3 class game. This helps to explain why the 6.5x55 is so successful on Scandinavian moose, which are about the size of North American elk.
And the 160 grain .264" bullet is superior to the 175 grain 7mm and 200 grain .30 caliber bullets, which are normally reserved for the largest and/or dangerous CXP3 class game. Remember those old stories about intrepid African hunters knocking over lion, buffalo and even elephants with 6.5mm rifles? Makes one think, doesn't it?
The .260 Remington
The .260 Remington is the newer of these two cartridges. Remington introduced it in 1997, although A-Square had earlier applied to SAAMI to standardize the then wildcat 6.5mm-08. The 6.5mm-08 wildcat had come to the attention of both A-Square and Remington due to its success in the demanding sports of metallic silhouette and NRA Highpower competition.
The .260 is based on a .308 Winchester case necked down to accept .264" bullets. Like the .308, its rim diameter is the standard .473" and rim thickness is .054"; its shoulder angle is 20 degrees. The .260's neck is .2595" long, or slightly less than one caliber (which would be .264"). The case length is 2.035" and the maximum cartridge overall length (COL) is 2.8". The latter specification allows the .260 to function in modern short action rifles.
Federal, Remington, and Speer offer .260 factory loads driving a 140 grain bullet at a MV of 2750 fps. In addition, Remington offers a 120 grain bullet at a muzzle velocity of 2890 fps. Reloaders can safely achieve velocities similar to these factory loads. The SAAMI maximum average pressure for the .260 is 52,000 cup.
Among the major rifle makers in the U.S. market, Remington offers the .260 in their Model 7 and Model 700 bolt action rifles; Ruger offers it in their Model 77 and Kimber chambers their Model 84 for the .260 Remington cartridge. Browning, Savage, and Winchester have offered .260 rifles in limited numbers in the recent past.
The 6.5x55 SE
The 6.5x55 was adopted as the service cartridge of Sweden and Norway in 1894. It subsequently become a very popular sporting cartridge in Scandinavia, and eventually caught on in the rest of Europe and around the world. It also became popular in Europe for centerfire rifle target shooting at the highest levels. In the U.S. it is generally known as the "6.5x55mm Swedish Mauser."
Military loads initially came with a heavy, round nose bullet weighing around 160 grains. Later, a 140 grain spitzer bullet replaced the old projectile and kept the 6.5x55 competitive with the 7x57 Mauser, 7.62mm NATO, .30-06 Springfield, .303 British, and 8x57 JS Mauser until the infantry rifles for all of these cartridges were retired from use by their various governments.
Despite its age, the 6.5x55 is a modern looking rimless cartridge with a sharp 25 degree shoulder angle. Its rim diameter is slightly oversize at .4803" and slightly thicker than usual at .0591". Fortunately, this minor deviation from what later became the norm does not prevent its use in most modern bolt action rifles. Neck length is .3079", well in excess of one caliber in length and ideal for holding long bullets. The case is 2.1654" long and the maximum COL is 3.15", so the 6.5x55 cartridge is too long for short action rifles. Today it is typically offered in standard (.30-06) length actions.
Most ammunition manufacturers load for the 6.5x55. Typical U.S. factory loads for the 6.5x55 from Federal, PMC, Remington, Speer, and Winchester drive a 139-140 grain bullet at a muzzle velocity (MV) of 2550-2600 fps. Higher performance Light Magnum loads from Hornady advertise a 129 grain bullet at a MV of 2770 fps and a 139 grain bullet at a MV of 2740 fps.
Norma of Sweden offers a 139 grain bullet at a MV of 2854 fps, a 140 grain bullet at a MV of 2789 fps, and several different 156 grain bullets at MV's ranging from 2526 fps to 2644 fps. The latter are widely used for moose hunting in Scandinavia. RWS of Germany offers several 6.5x55 loads including a 127 grain bullet at a MV of 2850 fps and a 154 grain bullet at a MV of 2670 fps. Sellier & Bellot of the Czech Republic loads a 140 grain PSP bullet at a MV of 2645 fps. These are typical of European 6.5x55 loads, which on average are loaded to higher pressure than standard U.S. factory loads.
In the U.S., the Dakota, Ruger and Winchester chamber their rifles for the 6.5x55. In addition Blaser, CZ, Howa, Sako, Sauer, and Tikka offer 6.5x55 rifles for sale in the U.S. market. These and other makes are available in Europe.
Beginning in the 1950's, after they were retired from active duty use, thousands of old Norwegian and Swedish military rifles in 6.5x55 were made available to the civilian market. Most common among these are the Swedish Mauser Models 1896 (29" barrel) and 1938 (24" barrel). Although old, these are well made bolt action rifles with dual front locking lugs in the usual Mauser pattern. The Norwegian Krag-Jorgensen rifle is not as strong as the Swedish Mausers and should only be used with moderate pressure loads.
Reloaders with old military rifles can safely achieve velocities similar to the standard U.S. factory loads. In the U.S. the maximum average pressure (MAP) for the 6.5x55 is held to only 46,000 psi (in deference, I believe, to the Krag action), but reloads for modern hunting rifles such as the Ruger M77 and Winchester Model 70 can safely be taken to 50,000 cup. This allows reloaders with modern rifles to equal and sometimes exceed the ballistics of the European factory loads.
As can be seen from the above summary of common factory loads for both cartridges, the ballistic potential of the two cartridges is essentially identical. If there is any advantage either way, it might be in favor of the .260 with light weight bullets (less than 120 grains) and in favor of the 6.5x55 with heavy bullets (in excess of 140 grains). For the medium weight bullets most commonly chosen for hunting CXP2 class game, ranging from 120 to 140 grains, there is little to choose between the two calibers.
Depending on whose reloading data you use, in either cartridge reloaders can drive 120 grain bullets to maximum MV's of around 2900-3000 fps. 125-129 grain bullets can be driven to maximum MV's of about 2800-2900 fps. 140 grain bullets can be driven to a maximum velocity of about 2700-2800 fps. And the heavy 154-160 grain bullets to MV's in the 2400-2600 fps range.
The Sierra Edition V reloading manual, for example, shows maximum loads for a top MV of 3500 fps for their 85 grain bullet, 3200 fps for their 100 grain bullet, 3000 fps for 120 grain bullets, and 2700 fps with 140 grain bullets for both calibers. For their 160 grain semi-spitzer bullet they show a maximum MV of 2450 fps in the .260 and 2500 fps in the 6.5x55.
For their 140 bullets, the most popular weight in both calibers, Sierra recommends a hunting load at a MV of 2700 fps for the .260 and at a MV of 2600 fps in the 6.5x55. For what it is worth, I would load either to about 2650 fps.
As you can see, all of these loads are so similar that no clear ballistic advantage exists for either caliber. The trajectory and killing power of the two cartridges is essentially identical. And both cartridges have successfully made their mark in centerfire rifle target shooting competition, so no superiority in terms of accuracy can be claimed.
Since the two cartridges can drive the same bullets to the same velocity, it stands to reason that their recoil is also pretty much the same. Both are mild and pleasant cartridges to shoot in rifles of normal weight. For example, an 8 pound rifle in .260 or 6.5x55 is quite a bit more fun to shoot than the same rifle chambered for the .308 Winchester cartridge.
The advantages of the newer .260 Remington cartridge would include its standard rim diameter and thickness (of no practical value to shooters, but possibly an advantage to rifle makers), and its shorter COL. The latter allows all short (.308 length) action rifles to be chambered for the .260 cartridge, and is the .260's principle advantage over the 6.5x55.
Why so many short action rifles are not offered in .260 I cannot understand. The .260 combines all of the best features of the common .25 to 7mm caliber short action cartridges in one very neat package. Perhaps part of the blame can be laid to Remington's almost non-existent attempt to promote the cartridge.
Customers for very light hunting rifles ("mountain rifles") are likely to favor the .260. A short action saves a couple of ounces in weight. The short action Kimber 84M (5 pounds 10 ounces), Remington Model 700 Titanium (5 1/4 pounds), and Remington Model 700 Mountain Rifle (6 1/2 pounds) illustrate the point. For comparison, the long action version of the Remington Mountain Rifle weighs 6 5/8 pounds, or two ounces more than the short action version.
Using an 85 grain bullet at a MV 3400 fps the .260 can challenge the .243 Winchester and 6mm Remington as a long range varmint cartridge, and with premium 140 grain bullets it can, like the 7mm-08 Remington and .308 Winchester, be used as an elk cartridge. In addition, it is probably the single best mountain rifle cartridge available today. How much more can anyone realistically ask?
The 6.5x55 cartridge can also be used successfully on game from groundhogs to elk with appropriate bullets. It is too long for short action rifles, but that is not entirely a disadvantage. The additional weight of the standard length action also means less recoil.
The extra action and magazine length, coupled with its relatively long neck, may allow the 6.5x55 to more efficiently handle heavy bullets. Heavy bullets do not intrude as far into the powder space of the longer 6.5x55 case. And the cartridge's long neck should help keep very long bullets, like the 160 grain Sierra semi-spitzer, precisely aligned with the axis of the bore. Shooters and reloaders have considerable latitude regarding the style and length of the bullets they select and the depth to which they are seated. That is the 6.5x55's main technical advantage over the .260 Remington.
Less esoteric is the fact that the 6.5x55 has been around longer and is consequently better known. There is a bigger choice of rifles and factory loaded ammunition in 6.5x55 than in .260, which is always an important advantage for any cartridge. RCBS, the big reloading die manufacturer, reports that the 6.5x55 has been among their top 30 calibers in die sales for many years.
For any prospective purchaser, the choice between the .260 Remington and 6.5x55 SE cartridges is likely to come down to which brand and model of rifle he or she prefers. For while there is almost complete overlap in the capabilities of the two cartridges, there seems to be very little overlap in rifles. (See my article "Choosing a 6.5mm Hunting Rifle" on the Rifle Information Page for more on the subject.)
In North America, Kimber, Remington and Ruger are the primary sources of factory built rifles in .260 caliber. CZ, Howa, Ruger, Sako, Sauer, Tikka, and Winchester are the most common sources for 6.5x55 rifles. Only Ruger offers their standard bolt action hunting rifle, the M77R Mk. II, in both calibers. So for everyone not buying a Ruger M77R, the choice of rifle will automatically determine the caliber. The good news is that both are outstanding cartridges.
Copyright 2003, 2012 by Chuck Hawks. All rights reserved.