Improved accuracy

In the 1900s, developments made in the industry were fast. Rifles became more accurate, and with the improvements in optics, this improved accuracy was used more extensively. The increased accuracy also meant an increase in firing distances. Also, questions on the adequacy of the performance of existing calibers became topical.

The increase in firing distances created the need for cartridges to bring bullet output velocities to a level higher than conventional cartridges. This time is known in the firearms press as magnum mania, as many manufacturers launched a lot of magnum cartridges in a very short time. The most popular of these are still popular today.

The biggest competition in the market was between the two largest firearms manufacturers in the United States at the time. Remington and Winchester both developed a whole series of new calibers, typical of which was that Remington used millimeter measurements in the designations of their cartridges, and Winchester refrained from imperial units of measurement.

Transformation

In the 1960s, there was a transformation going on under the gun, which was associated with general changes in the US industry. This forced manufacturers to design more production-efficient firearms, and, in part, develop new cartridges for marketing reasons. The new rifles gained greater visibility when they were introduced in new and more capable calibers.

At this time one of the most successful cartridges was the 7mm Rem Mag. This caliber perfectly combines the flat trajectory of the bullet, the more pleasant firing of 30-caliber magnums and the greater mass of bullets compared to the traditional .270 Win. At a time when the weight of bullets played the greatest role in the target effect, this issue was of great importance.

We wanted that cartridge to be comparable in firing range to the 30-06, which has often been seen as a milestone for the recoil that people are willing to put up with, on average. It was supposed to be close to the .270 Winchester in terms of external ballistics, but in terminal ballistic, it had to be closer to the .300 magnums. With 7mm bullets and a shortened casing based on .375 Holland & Holland, this combination was made possible.

The 7mm Rem. Mag. gained popularity especially in elk hunting (wapiti), where the caliber qualities were successfully demonstrated. A good velocity in open terrain for longer distances and good penetration of heavy 7 mm (.284") bullets were the combination that attracted the hunters of this large, prestigious and very tenacious game. The popularity was also substantially influenced by the coverage received by the caliber in the press. The caliber gained the support of several supporters who embraced the caliber and filled the pages of firearms and hunting magazines, with amazing stories about this new caliber.

Remington Magnum

The 7mm Remington Magnum uses the same .284" bullet diameter as the previously known European 7mm bullet cartridges. The most famous of these was the 7x57 Mauser. In that slower 7 mm cartridges typically used bullets weighing 140 gr, the 7 mm Remington Magnum could use 160 gr bullets, which were actually optimal for the characteristics of this caliber . High SD (sectional density) to ensure penetration, high BC (ballistic coefficient) to ensure flight characteristics and high energy even at long firing distances were the strengths of this caliber. This was crowned by a large enough powder capacity to bring the bullet to the required speed.

Despite its long-distance reputation, one should always remember the period the calibers represented at the time of their release. In the 1960s, for example, it was still typical that most of the bullets represented a so-called “cup core structure”, so the durability of bullets often became a problem at high velocities. This was especially problematic with magnum cartridges which were particularly tough in terms of bullet resistance at impact. Because of this, the 7 mm Remington Magnum was very often loaded with 175 gr bullets, which, although they offered penetration, were no longer optimal as long range bullets. Of course, comparisons must be made with similar bullets of this era. At that time, it was typical that for many other calibers, weight compensated for the durability of bullets and ensured penetration on game.

Comparing the 7 mm Remington Magnum with other magnum cartridges, one can better understand its position. For example, Winchester's 6.5 mm bullet-firing .264 Winchester Magnum was considered inferior to 7mm in terms of its effect on game but the .300 magnums were significantly heavier to shoot with lots of recoil. So, the 7mm magnum was a good compromise in many respects.

It speaks a lot about the versatility of the cartridge that until the 1990s it was popular in many long-range hunting rifles and also in shooting sports with long shooting distances. To some extent the 7mm Rem Mag has also seen military use as a chambering for sniper rifles, but it hasn't been widely used in this area, although its features would be suitable for that job as well.

With the development of bullets, the 7 mm Remington Magnum has gained new life. Today the design of bullets has changed in a wide spectrum and the failure of bullets at high impact velocities is no longer a problem. It can be said that many tough and durable bullets benefit more from the higher impact velocities offered by magnum calibers. At the same time, bullet weights could be decreased, offering ballistic advantages an order of magnitude at longer shooting distances.

Versatile and purposeful hunting caliber

Today, it can be said that the 7 mm Remington Magnum is a very versatile and purposeful hunting caliber. It works for all the big game in the Northern Hemisphere with 160 grain bonded bullets or 140 grain all-copper bullets. For the size of a deer, it can be made most suitable by using bullets that are a tad lighter than these, and if necessary, it is also possible to load this cartridge with varmint bullets for the occasional predator hunt. Also in African plains game hunting, the 7 mm Rem Mag is quite a popular caliper.

From a shooter's point of view, the 7mm Remington Magnum is still a viable option when looking for a good balance between a strong target effect and decent shooting comfort, and this is precisely the 7mm that has the biggest advantage over larger and smaller diameter magnums. In practice, the difference in efficiency is difficult to observe compared to, say, 30-caliber magnums, but the ammunition is typically more comfortable to shoot. At long firing distances, a flat trajectory makes it easier to hit, as the required trajectory compensation is moderate, and the effect of the wind is often not unreasonable either.

From the reloader's point of view, the 7 mm Rem Mag is an easy caliber, as its component availability is excellent and, for example, there are plenty of gunpowder grades available for reloading. The most suitable gunpowder is a bit slower than typical 4350 powders, which are marketed as magnum gunpowder by several manufacturers. In any case, it is easy to reload and instructions can be found from us at Sako so we can recommend you with reloading data.

Today, there is one outdated feature in this caliber, and that is the belted case, which to some extent causes headaches among reloaders. The headspace of the cartridge is determined by the belt and often there is unnecessary leeway between the cartridge chamber and the cartridge's shoulder. This leads to the case stretching typically on the very first shot. This reduces the durability of the case and this must be taken into account when considering the service life of the case being used.

In terms of available rifles, the 7mm Rem Mag is an extremely easy caliber to find among our Sako and Tikka rifles. The differences in availability compared to, for example, the .300 Winchester Magnum are national, meaning it is very typical that the popularity between these two calibers differ regionally. On the other hand, many special rifle models for long range hunting are only available in a few magnum calibers, of which the 7 mm Rem Mag is almost invariably one.

Author: Arto Määttä - published on 4.4.2023