Compared: 6.5-284 Norma and 6.5mm Rem. Mag.
By Chuck Hawks
I recently read a passage in one of the print magazines describing the 6.5-284 as "scorching hot." Considering that it was being mentioned with the likes of the .300 Win. Mag. and .338 Laupa Mag., the author's singling out the 6.5-284 for such an appellation got my attention and, admittedly, inspired this comparison.
Let's cut through some of the print mag hyperbole and establish one fact at the outset: the .6.5-284 and 6.5mm Rem. Mag. are high velocity cartridges, but the real scorchers in 6.5mm are the .264 Winchester Magnum and 6.5x68mm Schuler (RWS). These standard length magnum cartridges simply have greater case capacity than the Norma and Remington short action numbers and are ultimately capable of higher performance if loaded to the same maximum average pressure (MAP).
The 6.5-284 Norma and 6.5mm Rem. Mag. are actually second tier "hot" 6.5 cartridges. They are, however, high performance numbers delivering ballistics similar to the .270 Winchester, which is nothing to sneeze at and certainly commendable from a short action cartridge.
The 6.5-284 Norma
This is simply the wildcat 6.5mm-284 civilized by having been submitted to CIP by Norma of Sweden for standardization. (CIP is the European equivalent of SAAMI.) Apparently the cartridge has not been an overnight success as a hunting rifle cartridge, despite its success as a long range match cartridge, as I was unable to find any major rifle manufacturer who offered a hunting rifle in 6.5-284. Savage does offer an F-Class Open target rifle in 6.5mm-284 Norma. (See our review of that rifle on the Product Review Page.) It is quite popular in custom-built target rifles used in NRA High Power, F-Class and long range bench rest competitions. Perhaps this will lead to at least limited popularity among hunters and recreational shooters in the future.
The .284 Winchester (a true 7mm) was introduced in 1963 on a new case inspired by the .308 Winchester. It had the standard .473" rim diameter and cartridge overall length (COL) of the .308, but an oversize head diameter of .500", making the .284 a rebated rim case. That is the factor that ultimately limited its popularity with the more knowledgeable and less gullible generation of shooters of the time. (There are real drawbacks to rebated rim cases, as we shall see.) The .284 Win. was loaded to the unusually high maximum average pressure of 54,000 cup.
The .284 was intended to provide .270 Winchester performance in a cartridge that would work in the Winchester line of short action rifles, and it did. It was initially offered in the Winchester Model 88 lever action and Model 100 autoloading rifles and for a time in the Savage Model 99 lever action, but the cartridge was a commercial flop. However, the case was immediately necked up and down by wildcatters to create a whole series of .284 based wildcat cartridges, among the most successful and enduring of which has been the 6.5mm-284
6.5mm-284 Norma case dimensions are .500" at the head, .475 at the shoulder, 1.901" long from base to top of shoulder, plus a 35 degree shoulder and short neck to maximize powder capacity. The case length is 2.17" and the cartridge overall length is specified as 2.8". The latter figure is often exceeded when the cartridge is loaded for use in single shot target rifles. Case capacity turns out to be virtually the same as the 6.5mm Rem. Mag.
Norma offers two factory loads for the 6.5-284. The first drives a 120 grain Nosler Ballistic Tip bullet at a muzzle velocity (MV) of 3117 fps and muzzle energy (ME) of 2589 ft. lbs. The second uses a 140 grain Nosler Partition bullet at a MV of 2953 fps and ME of 2712 ft. lbs. These are obviously very high pressure loads, given the case capacity of the cartridge. (Cartridges standardized under CIP rules sometimes seem to have more generous pressure limits than those standardized by SAAMI.) The former is a fine deer and antelope (CXP2 game) load, while the latter is the "all-around" load for CXP2 and CXP3 game.
The 6.5-284 is clearly reloaders' cartridge, as factory ammo is expensive and hard to come by. In addition to Norma, Lapua and Hornady are supplying 6.5-284 brass for reloaders and practically all major bullet makers offer 6.5mm (.264" bullets). Reloading data is available in some of the major reloading manuals.
Since the 6.5-284 is based on a rebated rim case, it is only fair to comment on this case design. Anytime you make the rim smaller than the head of the case, it increases the area of unsupported brass at the extractor groove when the action is closed and locked, and decreases the area of the rim available for the bolt to push against when sliding the cartridge from the magazine, increasing the incidence of failures to feed. Thus rebated rim cases are inherently less reliable than normal rimless or belted cases for use in repeating rifles fed from box magazines, as are virtually all modern bolt action rifles. In addition, feeding problems are aggravated by a very sharp shoulder. No matter how assiduously the print magazines avoid mentioning these unpleasant facts, they are simply beyond dispute.
This does not make the 6.5-284 unworkable or unworthy of consideration for hunting non-dangerous game (although I would not recommend a rebated rim cartridge for hunting dangerous game). Its case is certainly a more functional design than the later .404 Jeffery based WSM, SAUM, and WSSM rebated rim short magnum cases introduced at the beginning of the 21st Century. The drawbacks of the 6.5-284's rebated rim case are merely among the facts that should be considered when selecting a hunting rifle cartridge. The rebated rim and sharp shoulder are not an impediment to operation in a single shot, bolt action target rifle.
The 6.5mm Remington Magnum
At about the time that Winchester was designing the unusual rebated rim .284 case, Remington was working on the first true short magnum cartridges. Their goal was essentially the same, to provide the performance of standard (.30-06) length cartridges for rifles using short (.308 length) actions.
Remington designers approached the problem from a different direction, mating a magnum size bolt face with a short stroke action. This allowed simply shortening the standard 7mm Remington Magnum case, and resulted in a straightforward cartridge design. The .350 Rem. Mag. and 6.5mm Rem. Mag. were the fruits of this labor.
The 6.5mm Magnum case has a standard magnum rim diameter of .532", a head diameter in front of the belt of .513", shoulder diameter of .496", base to top of shoulder length of 1.909", case length of 2.170", and a COL of 2.8". The shoulder angle is 25 degrees and the neck is short, like most modern cartridges.
These were the first short magnum cases, and actually provided slightly greater case capacity than the .30-06/.270 cases. They also avoided the drawbacks inherent in the rebated rim design of the .284 Winchester and the later rebated rim short magnum cases.
The 6.5mm Mag. hit the stores in 1966, first offered in the Model 600 Magnum carbine and later in the Model 660 Magnum and Model 700 bolt action rifles. Remington's high performance short action cartridges were no more successful in the marketplace than the .284 Winchester, although Ruger for a time also offered M77 rifles in the Remington short magnum calibers.
The 6.5mm Remington Magnum was given a new lease on life with the 2004 introduction of the Model 673 Guide Rifle. This improved and modernized take on the old Model 600 was offered in Remington's old short magnum cartridges as well as the new .300 SAUM, but was discontinued a couple of years later.
As I write these words, Remington is the only major ammo manufacturer loading the 6.5mm Magnum, and they offer only one load. This drives a 120 grain Core-Lokt PSP bullet at a MV of 3210 fps and ME of 2745 ft. lbs. This is a good load for CXP2 game, but anyone who owns a 6.5mm Remington Magnum rifle would be well served by reloading his or her ammunition.
Ballistics, bullets and reloads
Here are some common .6.5mm (264") bullet weights and their sectional densities (SD): 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 an important factor in bullet penetration and probably the most valid way to compare bullets of different caliber. While reloaders have access to a variety of bullet weights, the most popular choice for almost all 6.5mm cartridges remains 140 grains.
The top velocity listed for the 6.5mm Rem. Mag. in Hodgdon's 2006 annual reloading manual with the 140 Nosler Partition bullet was achieved with 49.5 grains of H4831 powder for a MV of 2943 fps at a MAP of 51,400 cup. The top velocity for the 6.5-284 with that weight bullet also used H4831 powder, in this case 45.0 grains for a MV of 2722 fps, MAP unspecified. This difference reflects the reluctance (or inability) of the Hodgdon technicians to load to the very high level of pressure and performance claimed for the Norma 6.5mm-284 factory loads.
The ballistics of the two cartridges are similar, with the 6.5mm Rem. Mag. having a slight advantage in barrels of equal length. (Note that the velocity figures in many reloading manuals were developed in short 18.5" or 20" carbine barrels.) This is best illustrated by the approximate 100 fps advantage offered by its 120 grain factory load. Reloading data varies rather widely for the 6.5mm-284. This reflects both its long history as a wildcat cartridge and its CIP standardization
6.5mm-284 Norma advantages and disadvantages
The biggest advantage of the 6.5mm-284 is that Norma offers two factory loads, giving a choice of 120 or 140 grain bullets to the shooter who is not a reloader. Unfortunately, Norma ammunition is not widely stocked in smaller sporting goods stores and by mass merchandisers in North America, so it can be difficult to find. For the long range target shooter, who is always a reloader, the 6.5mm-284 Norma is the cartridge of choice. There are multiple companies supplying 6.5mm-284 Norma brass to reloaders.
The 6.5mm-284's biggest disadvantage is the lack of readily available, mass produced rifles in the caliber. It's hard to shoot ammo for which rifles are unavailable. A custom built rifle is the obvious solution and the great majority of NRA Long Range High Power and F-Class Open competitors are shooting custom built rifles, but they are beyond the means of most recreational shooters.
6.5mm-284 cases can be formed from .284 Winchester brass, but .284 brass is only available from Winchester and it is in relatively short supply. Because the .284 is a unique case, 6.5mm-284 brass cannot be formed from any other case.
6.5mm Remington Magnum advantages and disadvantages
While the selection of factory built rifles in 6.5mm Rem. Mag. is very limited, at least they are available and Remington dealers and rifles are very common in North America. That is probably the biggest plus for the 6.5mm Magnum.
The selection of Remington factory loads is exactly one, and therefore one short of the two load choice available for the 6.5-284. But again, there are plenty of Remington dealers who can special order a supply of 6.5mm Mag. ammo for the customer who wants it.
A secondary advantage of the 6.5mm Rem. Mag. is that it is based on a conventional belted magnum case. It is stronger than the 6.5-284 case and avoids the potential feeding problems inherent in the 6.5-284's rebated rim and ultra-sharp shoulder design. In a pinch, 6.5mm Mag. brass can be formed from any standard belted magnum case.
Summary and final thoughts
The selection and availability of factory loaded ammunition for both cartridges are quite limited. Remington ammunition is more widely distributed in North America, while Norma offers two (rather than a single) bullet weight for the 6.5mm-284. Most users will find it necessary to special order ammunition for either cartridge from a full line dealer. Stocking dealers for these calibers are few and far between.
Specialty ammo maker Stars and Stripes offers factory loaded ammunition for both the 6.5mm-284 and 6.5mm Rem. Mag. in their Custom line. Call Stars and Stripes (954-917-1129) for details and prices.
Most hunters seeking a 6.5mm rifle with this level of performance will probably look for a used Remington rifle in 6.5mm Rem. Mag. caliber. Shooters who can afford a custom built rifle will be well served by either caliber as long as they are reloaders.
It is worth pondering what might happen if both calibers should be discontinued in the future. Given their lack of general popularity, that is a possibility.
Those reloaders who own 6.5mm Rem. Mag. rifles will not have much difficulty shortening and reforming cases from any of the standard belted magnum calibers from .458 Win. Mag. on down. They will be somewhat inconvenienced by the necessity of case forming, rather than simply buying new cases, but they will be able to use their rifles as before.
Should the 6.5mm-284 Norma cartridge be discontinued, however, the owner of a 6.5mm-284 rifle is in real jeopardy, as the .284 parent case is unique and even less popular than the 6.5mm-284. Ominously, .284 rifles have not been mass produced for probably 30 years and the caliber is down to one load produced only occasionally by one manufacturer (Winchester). The outlook for the .284 Winchester is bleak, which casts something of a shadow over the long term prospects of the 6.5mm-284 Norma as well.
Copyright 2006, 2015 by Chuck Hawks. All rights reserved.