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When Sweden upgraded their military service rifle, thousands of surplus 6.5x55 Swedish Mauser rifles were exported and sold abroad. The cartridge itself held almost a mystical appeal, an extremely long, sleek, deadly looking projectile housed in what looked like a cartridge case of reasonable powder capacity.
Although U.S hunters had access to the Swedish Mauser, ammunition was for a long time, hard to obtain. When American factory produced ammunition did finally become available, it was downloaded to such an extent that performance was abysmal. This was mostly based on a distrust of Swedish metallurgy. Regardless, U.S hand loaders were, like other hand loaders around the world, loading the 6.5x55 to full power. Several hunters praised the performance of the 6.5x55 in magazine articles which added to its allure.
When U.S, Australian and NZ competitive target shooters experimented with the 6.5mm bore, the results were outstanding. The 6.5 was capable of producing low bullet drop and low wind drift with minimal recoil. Accuracy with the most basic of 140 grain projectiles was excellent. That said, a number of competitive shooters were (and still are) great fans of the .308 Winchester case design. As it is a common practice for serious competitive shooters to utilize wildcat cartridge designs to obtain optimum performance, necking down the .308 case to 6.5mm was a predictable and natural progression.
The 6.5-08 wildcat produced identical velocities to the 6.5x55. Nevertheless, the benefits of the wildcat chambering included greater control of chamber tolerances during reamer design along with readily available inexpensive U.S brass. The wildcat cartridge could also be housed in magazine fed short action rifles although this was not a main concern.
By the end of the 1980’s, a small number of competitive shooters were enjoying the benefits of the 6.5-08 wildcat loaded with the 139 grain Lapua Scenar projectile. By the mid 1990’s, the wildcat had become well known in competition circles. The wildcat chambering was also beginning to appear in hunting rifles. As a typical example, the 6.5-08 was an ideal step up when re-barreling worn out .243 Winchester caliber rifles. The wildcat was well suited to the short action, utilized heavier and deeper penetrating projectiles than the .243 but with a similar flat trajectory along with mild recoil.
In 1996, Arthur B Alphin, director of A-Square Cartridges (USA) applied to have the 6.5-08 wildcat standardized by SAAMI as the 6.5-08 A-Square. A-Square was a member of SAAMI (Sporting Arms and Ammunition Manufacturers Institute) but for unknown reasons, the processing of Alphin’s application was very slow. In 1997, Remington (also a SAAMI member) made a similar application to standardize the 6.5-08 as the .260 Remington. Shortly thereafter, the Remington design was accepted and the cartridge dimensions standardized. Although A-Square lost naming rights to the wildcat, the odd situation was not turned into a major drama. Like other SAAMI members, A-Square continued to focus on the primary goal of safe design of firearms and cartridges.
Remington released the .260 Remington in 1997 as a hunting cartridge. The .260 was initially chambered in the Model 7 rifle followed by the M700. The 1997 marketing campaign promoted the .260 as being a compact short action cartridge producing less recoil than the .270 Winchester yet higher down range energies. The stainless synthetic Model 7 rifle utilized a short, ultra light weight action coupled with a 20” light weight barrel. Regardless of the 6.5-08’s popularity for target shooting, the .260 was not offered in the Remington 40-X target rifle, nor was any match grade factory ammunition introduced.
While the .260 achieved limited success, it did not deliver optimum performance. Remington factory ammunition for the .260 produced low velocities in the Model 7 rifle and for factory ammunition users, killing performance was somewhat mediocre. In fact, performance of the factory combination was not unlike the already anemic loads available for the 6.5x55.
For hand loaders, the .260 was not able to give any more performance than was already available from the 6.5x55. Nevertheless, for some hunters the light weight Remington rifles, both the M7 and M700, offered several desirable features in comparison to sporterised ex-military Swedish rifles. It is this group of hunters that utilized the .260 the most.
Currently, the .260 has a small following amongst hunters world wide. In competitive shooting, both the 6.5-08 and .260 have to a large extent, been superseded by the 6.5-08 Ackley Improved or .260 Ackley Improved. Although both the 6.5-08 and .260 are the same cartridge, it is important that readers be aware of the fact that in target rifles, there are several slight variations in chamber dimensions according to individual customer specifications. A target rifle marked .260 Remington “should” be able to safely fire Remington factory ammunition or hand loads using 7mm-08 brass while rifles marked 6.5-08 may on occasion, have minimum dimension chambers which can potentially produce dangerous pressures using ordinary components.
The .260 Remington has a slightly shorter but slightly wider case than the Swedish 55mm case. Ultimately, the .260 and 6.5x55 produce the same velocities.
It has been said that the 6.5x55 can produce better velocities than the .260 when hand loaded with 160 grain bullets however this is not necessarily true, nor is it a useful statement. Both the Swede and .260 produce low velocities with 160 grain bullets and while the premise of a 160 grain 6.5mm projectile may sound appealing, the blunt, low BC designs of the available 160 grain 6.5mm projectiles make this bullet weight the least versatile - in the 6.5mm bore anyway.
The .260 Remington has given hunters access to the 6.5mm bore in an over the counter manner. Factory sporting rifles and theoretically suitable ammunition are readily available. The Remington rifles have many desirable features. The M700 rifle in stainless synthetic is able to withstand far greater long term abuse and neglect than the sporterised Swede. The M700 can be built lighter than the Swede although the extreme version, the Model 7, can suffer accuracy problems due to the exceptionally light weight barrel.
For factory ammunition users, this cartridge does not quite deliver optimum performance with Remington Factory ammunition. Killing power is far closer to the .30-30 rather than the .270 Winchester that is often used as a comparison. For hand loaders, performance can be enhanced considerably. That said, as previously stated in the 6.5x55 performance text, hunters must take care not to become over confident in the abilities of the 6.5mm bore.
The mild 6.5’s give fast killing at close ranges but definitely lose the ability to produce wide wounding at ranges beyond 200-250 yards when using hunting projectiles. Light 120 grain bullets hand loaded to between 2950fps produce fast kills on lighter medium game but most 120 grain bullets produce shallow penetration. The exception to this is the 120 grain Barnes TSX.
130 grain bullets hand loaded to 2850fps have neither the high SD’s and BC’s of the 140 grain bullet weight or high velocity achieved from hand loaded 120 grain bullets. Performance is identical to budget .270 Winchester factory ammunition at 2900fps.
The 140 grain bullet hand loaded to between 2750 and 2800fps is the most versatile bullet weight for the .260 offering the best balance of wounding versus penetration. That said, kills beyond 200 yards can be slow while conventional projectiles, regardless of SD, often fail to produce deep penetration.
At ranges beyond 200 yards, the hunter should aim to break the foreleg bones of game. Both rear lung and neck shots often result in very slow killing at extended ranges.
Performance of the .260 can be increased considerably by creating loads for specific applications. Both the .260 and Swede give excellent results when used this way. The negative aspect of this method is that versatility can be lost, especially when large variations in game body weights might be encountered at varying ranges. As an example, the .260 loaded with the 140 grain A-max at 2800fps produces extremely wide wounding, fast killing and adequate penetration on medium game at ranges between 0 and 400 yards, producing optimum performance between 200 and 400 yards. This is an excellent load for lighter bodied deer species. However the 140 grain A-max is not reliable on tougher animals such as mature wild boar at close to moderate ranges, hence this load suits a specific application.
Current factory loads from Remington's 24" test barrels feature the 120 grain Accutip boat tail at 2890fps, the 140 grain Core-Lokt at 2750fps and the 140 grain bonded core Core-Lokt ultra at 2750fps. Unfortunately in the short barrel of the Model 7 these loads lose at least 140fps giving the 120 grain bullet 2750fps and the 140 grain bullets 2600fps. In the M700 rifle variants with 22” barrels, the 120 grain bullet gives around 2800fps and the 140 grain loads around 2670fps.
The Accutip is extremely similar in design and performance to the Hornady SST. This load is best suited to light bodied game as penetration is somewhat limited. The Accutip has the potential to produce flat trajectory and excellent longer range performance but is handicapped by the low muzzle velocities.
The 140 grain Core-Lokt is perhaps the best conventional 6.5 projectile on the market and out penetrates any other, giving excellent expansion and wide wounding. Again, performance is limited by low velocities which limit the wounding potential of this otherwise useful game bullet. The Core-Lokt Ultra is an excellent projectile but because of low muzzle velocities, creates a much narrower wound than conventional projectiles. Surprisingly, at these velocities, core bonded projectiles do not out penetrate conventional projectiles by a noticeable margin. The main benefit of the Ultra is its extra insurance on heavy bone with no risk of bullet blow up. When used on light to medium sized deer, the Ultra can be slower killing than the traditional Core-Lokt in this combination.
A last note on Remington Factory ammunition - in both the .260 and 7mm-08, low velocities have in the past led to poor case to chamber obturation (sealing) in some rifles. The small amount of gas leakage combined with low pressures can allow powder fouling to build up in the case neck area of the rifle chamber. The expansion of the case neck compounds the problem as it becomes a ram, compacting powder fouling against the neck area of the rifle chamber. In these situations, a once fired Remington case will be tight at the case mouth and will not slip easily over a projectile from an unfired factory round. When powder builds up in this manner, pressures become high and accuracy extremely poor. Those who use Remington factory ammunition at this time of writing are advised to carefully monitor chamber fouling and use suitable cleaning methods, preferably, a .277 caliber bristle brush and solvent rotated about the chamber.
Like most cartridges based on the .308 Winchester case, the .260 is relatively straight forwards to hand load, giving predictable results. Brass for the .260 is readily available but can also be quite easily formed from either .243 or 7mm-08 brass. The parent .308 brass is suitable for necking down to .260 however the extra thickness of the .308 case neck needs to be removed to avoid potentially dangerous pressure conditions.
The .260 Remington produces optimum results with medium slow burning powders in the 4350 range. Longer barreled (24-32”) custom rifles obtain excellent results with H4831sc. From the original Model 7 rifle, the .260 is able to produce 2900fps with 120 grain bullets and 2700fps with 140 grain bullets. That said, some Model 7 rifles have too light a contour barrel to give optimum accuracy with high pressure loads.
One factor that must be taken into consideration when reloading for short barreled rifles is that it is very common for individuals to use working loads that are higher in pressure than SAAMI recommendations. In some instances, hand loaders will sacrifice long case life for optimum velocities. Whether this practice is right or wrong is irrelevant; the fact is that this is a common practice with short barreled rifles in the calibers .243, .260, 7mm-08 and especially the .308 tactical rifles. Most modern rifles will take this abuse but it goes without saying that maximum loads developed for one rifle are often far from suitable for another rifle.
In longer 22” barreled rifles, the .260 will comfortably produce 2950fps with 120 grain bullets, 2850fps with 129/130 grain bullets and 2750fps with 140 grain bullets. Some rifles will produce another 50fps with careful experimentation which, as always, should be done in conjunction with a chronograph along with attention to pressure signs. In 24” barrels, 120 grain bullets can be driven at 3000fps with relatively mild pressures with 140 grain bullets producing 2800fps and mild pressures, particularly when using slow burning H4831sc.
Because the .260 essentially duplicates the Swede, bullet performance is discussed within that text.
As previously mentioned, the .260 Ackley Improved has become a very popular cartridge for both competitive target shooting and also amongst intermediate long range hunters. The improved case does not necessarily create higher velocity potential in this already highly effective case design however the sharp 40 degree shoulder angle minimizes trimming operations, maximizes case life and with excellent head spacing, has high accuracy potential. The slight change in case shape can also create more consistent burning characteristics when using slow burning powders.
For target shooters, the greatest velocity gains from the AI are obtained through the use of a long barrel. For long range hunters using shorter 24-26” barrels, as is often the situation with hunters using improved cartridges, it is common practice to work at maximum pressures that are only slightly below the point at which undesirable case deformation occurs. In either situation, velocities for the AI tend to duplicate the 6.5-06 with 140 grain bullets achieving 2950fps.
Note: See 6.5x55 tables for suggested hand loads.
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