Metric bore diameters have never really been a huge success here in America; perhaps it's our natural resistance to the metric system, or simple American pride. Nonetheless, the very nature of the 6.5mm (.260 cal.) bullets makes it a wonderful choice.
While the 6.5 Creedmoor is gobbling up the lion's share of attention within this bore diameter, there are many other, and many older, viable choices. It has been overlooked for far too long here in the U.S., being an excellent choice for the most popular game animals here. Let’s have a look at the gamut of popular 6.5mm cartridges, highlighting the strengths and weaknesses of each.
6.5x55 Swedish Mauser
Bred for war, the 6.5x55 Swedish Mauser dates back to the late 19th century, yet remains one of the finest 6.5mm cartridges on the market. Offering the capability of driving the heavy 156- and 160-grain bullets to a muzzle velocity of just over 2,500 feet per second (fps)- it makes a good choice for an all-around hunting rifle. The Swede will shine with the 140-spitzers, pushing them to over 2,850 fps; this betters the Creedmoor’s velocity by over 100 fps, making the Swede a perfectly viable long-range cartridge. No, it won't run in an AR platform, but makes a great choice for the bolt guns.
6.5x54 Mannlicher Schoenauer
Released in the early 1900s as a military cartridge, the 6.5x54 earned a great reputation among hunters in Africa. W.D.M. 'Karamoja' Bell used one as an elephant rifle - though he preferred the .275 Rigby -taking many of the great beasts with it. The famous Kenyan Game Ranger A. Blaney Percival - brother of Philip Percival who hunted with both Theodore Roosevelt and Ernest Hemingway - used this cartridge as his lion gun. He relied on the Sectional Density of the 160grain solids for penetration, and preferred the light recoil of the rifle. The mild muzzle velocity - 2,400 fps with the 160-grain slugs - ensured that the soft point bullets performed well, without premature breakup. Though a rarity today, both the cartridge and the rifle are revered by collectors.
This was the Italian service cartridge, most famous for being used by Lee Harvey Oswald in the assassination of President John Kennedy. The Carcano got a reputation for being rather inaccurate, though having shot it I'd lay the blame on the rifle rather than the cartridge. Pushing a 162-grain round nose bullet at a muzzle velocity of 2,200 fps, the formula is sound, but the rifle, well, sucks. I imagine it would've done well in a properly built rifle.
.264 Winchester Magnum
Winchester released a series of magnums in the late 1950's based on a .375 H&H case, shortened to 2.500 inches; the .264 Winchester Magnum was necked down to hold 6.5mm bullets. Touted for its flat trajectory, the .264 Magnum picked up a reputation as a barrel burner - and driving a 140-grain at 3,200 fps one could easily understand why - and was quickly overshadowed by Remington's 7mm Magnum. Nonetheless, the cartridge is an accurate, flat-shooting, hard-hitting design, that will give good service if not shot to the point of meltdown.
6.5 Remington Magnum
Taking the shortened .375 case idea to a further extreme, Remington released the 6.5 Remington Magnum in 1966. Designed to run in a short-action rifle, the short, squat cartridge used the lighter 120 and 125-grain bullets. It was released in the Model 600 Carbine, using an 18.5-inch barrel, which didn't exactly take full advantage of the powder capacity of the case. Perhaps the shooting world wasn't ready for the short magnum theory; it never really caught on.
Wildcatters love to take a new case and neck it up and down; and when the .308 Winchester was released in 1952, it immediately received the treatment. The end result was a series of cartridges from .243 up to .358, some being quickly adopted and others remaining wildcats for a good number of years. The .260 Remington is simply the .308 Winchester case necked down to hold 6.5mm bullets, and represents what may be the ultimate balance of bore diameter and powder capacity for the case. It is seriously accurate and can be chambered in the AR-10 platform, though seating the longest bullets can pose an issue due to the restraints of the magazine length. As a hunting round, the .260 Remington makes a whole lot of sense, as it's easy on the shoulder, flat shooting, and its bullets will retain lots of energy downrange. While it's been overshadowed by the Creedmoor as a long-range cartridge, I wouldn't hesitate to head afield with a good .260 Remington.
This is another gem from the wildcatter's drawing board, being the .284 Winchester cartridge necked down to hold 6.5mm bullets. It quickly became the darling of the long range shooting community, having a case capacity to launch the sleek 140-grain target bullets to over 2,900 fps in a long-barreled rifle. Using a wide body and a rebated rim, the 6.5-284 Norma isn't quite as hard on a rifle's throat as the .264 Magnum, but can still deliver the goods at 1,00 yards and beyond. This is my personal favorite of the 6.5mm lineup, as it makes an excellent hunting cartridge as well as a target round.
This one probably needs no introduction, as it seems to have taken the target world by storm. Based on a shortened .30 T/C cartridge, and designed to fit in the AR magazine, even when loaded with longer bullets, the Creedmoor has enough case capacity to reach out and touch someone, while offering minimal recoil. It works well in bolt guns as well as the gas guns, pushing the 140-grain pills to just about 2,700 fps (depending on barrel length). With us for just over a decade, the Creedmoor represents the current wave of cartridge design, relying on bullet conformation and retained energy rather than initial horsepower.
Alexander Arms introduced the Grendel in early 2004, as an accurate, low-recoiling cartridge for the AR platform, capable of delivering excellent accuracy out to 800 yards. The stubby cartridge will drive the 120-grain bullets to 2,700 fps, and the 130-grain bullets to just over 2,500 fps, but the beauty of the design is its lack of recoil. Capitalizing on the wind deflection characteristics and retained energy of the 6.5mm bullets, the Grendel runs surprisingly well from such a short cartridge. Yes, it's a niche cartridge, but a cool one.
This one was a bit of a flash in the pan, as far as commercial rifle and ammo go. It has been around, in wildcat form, for quite some time, though A-Square standardized the dimensions in the late 1990s. It is a solid design, giving fully respectable ballistics in a common case that is easy enough to make with a good set of reloading dies. Being the .30-06 Springfield case necked down to hold 6.5mm bullets, I'd have thought it would be more popular than it is - almost all of the '06 offspring has done well),but alas, it, along with the A-Square company, seem to have faded into the sunset. I know some shooters who still shoot and hunt with it, but commercially, it's virtually gone.
Using the beltless .404 Jeffery case (a particular favorite of mine) as a platform for their series of proprietary cartridges, Nosler introduced the .26 Nosler in late 2013. A 2.590-inch case - capable of fitting in a long-action receiver - blown out, and using a rebated rim, the .26 Nosler is a speed-demon for sure. The 140-grain bullets leave the muzzle at 3,300 fps, making for a flat-shooting magnum class rifle that will buck the wind very well. It's accurate, for sure, but like the .264 Winchester Magnum, you can expect that barrel life will be shorter than that of the milder 6.5s. However, if you want a fast, flat 6.5, the .26 Nosler will definitely fit the bill.
6.5-300 Weatherby Magnum
The Weatherby cartridges have always been about speed, and the 6.5-300 is no disappointment. The .300 Weatherby is a time-proven design, and Weatherby necked it down to hold 6.5mm bullets, resulting in the fastest 6.5mm cartridge commercially available. The famous Weatherby double-radius shoulder is there, along with the belt that was carried over from the Holland & Holland design. It will send a 140-grain bullet screaming from the muzzle at almost 3,400 fps, resulting in a trajectory that is a dead-hold out to 350 yards. All that comes at the price of increased recoil andshort barrel life, but if you want a hot-rod, this is your baby. While probably not practical as a target rifle - just because of barrel erosion and recoil - is will definitely reach out to sane hunting ranges with ease.
Introduced at the 2018 SHOT Show, Hornady's 6.5 PRC is based on the .300 Ruger Compact Magnum case, neckedto hold 6.5mm bullets and designed to run in a short-action rifle. Hornady loads their 143- and 147-grain ELD Match and ELD-X bullets, to a muzzle velocity of just over 2,900 fps, putting the 6.5 PRC on equal plane with the6.5-284 Norma. The PRC will deliver a trajectory highly reminiscent of the .300 Winchester Magnum, at least at hunting ranges. Out further, the PRC and its high B.C. bullets will show an advantage in trajectory and win deflection. Think of the PRC as the big brother to the Creedmoor, perfect for the gun games like the Precision Rifle Series and for any hunting scenario where a 6.5mm is warranted.
So, if you want to enjoy the 6.5mm bore diameter and all it has to offer to hunters and target shooters, there is absolutely something for everyone, from the recoil sensitive to the speed freaks and everyone in between. The 6.5mm bullets have been satisfying shooters for 120 years, and will continue to do so for another 120!