6mm Remington
The 6mm Remington rifle cartridge, originally introduced in 1955 by Remington Arms Company as the .244 Remington, is based on a necked down .257 Roberts cartridge (itself a necked-down 7×57mm Mauser) using a .24/6mm bullet. Known for a combination of high velocity, long range, flat trajectory, and accuracy, it is suitable as a dual use hunting cartridge for both medium-sized big game and varmints. When used in the less common earlier slow twist barrels, it offers exceptional range for varmint applications. While not as commercially popular today as the .243 Winchester, the  6mm Remington enjoys a slight ballistic advantage and continues to be popular with handloaders and custom rifle builders. Developmental history. By the early 1950s, there had been a significant amount of experimentation and 'wildcatting' in developing the .24 caliber bullet as a dual purpose hunting round. Popular cartridges necked down for this purpose included the .257 Roberts (based on the 7x57mm Mauser) and .308 Winchester.] Fred Huntington of RCBS had developed what was known as the .243 Rock Chucker wildcat cartridge. This was a necked down .257 Roberts casing shooting a .24/6mm bullet. This ultimately became the  .244 Remington. Mike Walker, who had previously designed the Remington Model 722, 'productized' Huntington’s wildcat cartridge and adapted the Model 722 chambering for it in 1955. The existing Remington Model 722 was chambered for the new .244 Remington cartridge with a 1 in 12-inch twist. Remington originally offered this cartridge with 75 grain bullets for varmints and 90 grain bullets for medium-sized big game such as deer and antelope. ] Remington determined that a 90 grain soft point .244 hunting bullet was well suited for medium-sized big game hunting purposes. For the length and weight of its  90 grain soft point hunting bullet, Remington selected a 1 in 12-inch twist. By selecting the slowest twist possible, Remington was seeking to avoid excessive spin. By avoiding excessive spin they were able to maximize velocity, range and accuracy of their 90 grain big game hunting bullet as well as lighter varmint loads. Public perception and understanding of ballistics in the 1950s did not agree with this approach. By 1958, Remington was obliged to increase the 722s twist to 1 in 9 inches, well in excess of what is needed to stabilize a 90 grain bullet. Remington continued to  offer factory ammo in 75 and 90 grain bullets. Remington also added several other rifles chambered for the .244 cartridge including the Model 740, Model 742, Model 760 and finally the Model 725. However, by 1962, presumably due to lack of sales, Remington no longer chambered rifles for .244 cartridge. In 1963, on the heels of its successful first year launch of the new Remington Model 700 bolt action hunting rifle, the .244 was re-introduced but renamed 6mm Remington. The 700 continued with the 1 in 9-inch twist and Remington also introduced new 6mm ammunition loaded  with a 100 grain Cor-Lokt bullet. The new model could also shoot any .244 ammunition. Previous Remington 722 rifles made after 1957 with 1 in 9-inch twist could also shoot the newer 6mm 100 grain ammunition. Remington labeled their new 100 grain bullet ammunition as "6mm" when introduced. However Remington continued to manufacture and label the 75 and 90 grain bullet ammunition as ".244" for a number of years. From the late 1960s until the early 1970s Remington transitioned to labeling all such ammunition regardless of bullet grain weight only as "6mm." Performance. Velocity. The  following table provides performance specifications published in Remington catalogs in 1955 and 1963, the first years the respective cartridges were introduced to the public. Recoil. The 6mm Remington has the advantage of a relatively low recoil of about 10 ft/lbs depending on load. Some gun writers, including Chuck Hawks of "Guns and Shooting Online" believe that this has the advantage of allowing shooters to be comfortable with the rifle without developing a flinch, allowing them to focus on accurate shot placement. Comparison. Inevitably the 6mm Remington cartridge is highly comparable to the 243 Winchester. Both were intended  for the same purposes, both developed out of wildcat loads and both were introduced in the same year. In 1963 Remington produced both cartridges using their own sourced brass, primers, powder and bullets. This allows for comparative data from a single manufacturer and in the case of the 100 grain bullet, identical bullets were even used. The following table summarizes performance data published in Remington's 1963 catalog: The following summarizes comparative trajectory data between the 6mm Remington and .243 Winchester using the same 100 grain bullet: Market acceptance. The .244 Remington lagged in the marketplace of the mid-1950s . Winchester also introduced a similar dual purpose cartridge of the same caliber with greater success in 1955, the .243 Winchester, but with 80 and 100 grain bullet options for its Model 70 with a 1 in 10-inch twist to allow for the slightly heavier bullet. Two commonly held beliefs discussed below seek to explain the market success of the Winchester over the Remington cartridge. Varmint vs Big Game cartridge. In the mid 1950s, Remington singled out and marketed the .222 Remington, not the .244 Remington for varmint applications in catalogs and flyers. In present times, many mistakenly believe Remington  originally developed and marketed the Model 722 in .244 primarily as a varmint rifle. By the 1990s, even Remington itself sometimes promoted its 6mm rifles specifically for varmint applications thus further propagating the perception. While this lingering perception is not accurate, it does serve to underscore contributing factors to beliefs held since the mid-1950s. As noted earlier, Remington developed two .244 loads, one using the heavier 90 grain bullet specifically designed, marketed and intended for medium-sized big game such as deer and antelope. As Remington saw the 90 grain bullet to be well suited for big game hunting  they elected to match the slowest twist to that length of bullet specifically and avoid excessive projectile spin in favor of velocity. A 1 in 12-inch twist was selected and used initially. Since the newly introduced .243 with its 100 grain bullet was also available, it is thought many consumers believed that to be the minimum mass needed to hunt deer. Likewise, the early Remington 722s often would not consistently gyroscopically stabilize 100 grain Spitzer bullets depending on their length and the original slower twist. While the rifles are now known to be inherently accurate with appropriate bullets, early  misguided attempts to shoot longer 100 grain bullets that might not stabilize, gave the cartridge a bad, if inaccurate, reputation. In December 1955, "Guns Magazine" writer, H. Jay Erfurth in an article titled "Two Varmint-Big Game Rifles" discussing the .244 Remington and .243 Winchester wrote "the Winchester bullet of 100 grains is the better one for deer and medium game than the 90-grain Remington pointed soft-point, though the differences seem mostly splitting hairs." He went on to write "With the 90 grain load, the 244 is a good deer cartridge and certainly effective on antelope and any  lighter game." Ultimately 90 grain hunting bullets such as the soft pointed Spitzer used by Remington are known to be well suited to medium-sized big game and the 722 to be an inherently accurate rifle. Plain vs Deluxe Rifle. The second explanation often mentioned involves the initial rifles themselves which were chambered for the .244 and .243 cartridges respectively. Remington selected the Model 722A and 722BDL when first introducing the .244 and Winchester relied upon their Model 70 for their .243. The Model 722A was often cited as ‘plain’ while the Model 70 was more upscale in comparison and  thus purportedly led to greater acceptance of the .243 in the market. However this fails to take into account several factors when the respective rifles were introduced in 1955. The Model 70 was offered with several trim levels of features all of which were above the more basic 722. However the Model 70 prices ranged from $124.45 for the Standard up to $184.65 for the Super. While the 722A Standard Grade was somewhat basic it was also considerably less expensive at $89.95. Given that both Remington and Winchester were developed a dual use rifle, it is logical  to expect that buyers seeking a single rifle for multiple uses would likely be more price conscious than a buyer able to afford multiple rifles. Remington also offered a more upscale 722BDL Deluxe Grade chambered for .244 with more features including figured walnut stock, sling swivels mounts and checkered stock making it more directly comparable to the Model 70. The 722BDL list price was $120.95, still less than any of Winchester’s .243 rifle offerings. Three years later Remington offered the 725ADL in .244, a feature rich model akin to the modern Model 700. Had the early rifles chambered  for .244 been more successful initially, critics could have just as easily pointed to Winchesters lack of value priced rifles in .243. Erfurth went on to write about the Model 722 in .244 Remington, describing it this way: "Remington's [.244] offering comes in the M722 which is one of the least expensive, yet most modernly designed, bolt guns on the market." The 721/722 rifle line was an overall success for Remington in various calibers and competitively priced as a value offering for the market. Firearms. Remington chambered at least twelve rifles for the 6mm cartridge. Bolt-action Rifles  Semi-automatic Rifles Pump-action Rifles Other manufacturers including Marlin, Savage, and Ruger have also chambered rifles for 6mm Remington over the years. Legacy. Ultimately the buying public of the 1950s responded more favorably to the .243 Winchester while the .244 struggled to gain greater market acceptance early on. Whether this was due to Winchester’s slightly heavier big game bullet or the differences in the aesthetic features of the initial rifles themselves or other factors altogether, it is difficult to say in retrospect. Remington was quickly responsive to early criticism by changing the twist rate in 1958 to  allow for heavier bullets, replacing the 722BDL with the even more upscale Model 725ADL rifle in 1958 and ultimately transitioning to the highly successful Model 700. Remington even re-branded the cartridge name itself for a fresh start with a 100-grain factory load as 6mm Remington. While the 6mm Remington cartridge never took over the .24 caliber dual purpose market lead from .243 Winchester, it was successfully sustained in production for nearly six decades. As compared to the 1950s, there is broader public insight and knowledge of ballistic information today. This has led to a greater appreciation  of the 6mm Remington. Hunters and long range shooters appreciate the cartridge capacity and ballistic advantage the 6mm Remington cartridge has. Handloaders benefit from a long cartridge neck which facilitates loading operations and one of the widest selections of bullets available in any caliber. Prized among some are the earlier slow twist version .244 rifles for their ability to push higher velocities with lighter loads due to a lack of excessive spin.