A Metric Marvel: 6.5x55 Swedish Mauser
October 15, 2015
Not many metric cartridges have achieved great popularity in the United States, despite the ballistic virtues of many of them. The 6.5x55mm Swedish Mauser has, however, gained considerable following stateside, with good reason. It offers a host of attributes that make it an ideal round for many hunting situations.
In Sweden and Norway, it is immensely popular for reindeer and moose, in Africa for plains game and stateside it has accounted for countless deer- and elk-sized critters. Not many would take it to a prairie dog town or use it on large bears, but for most everything in between, it does just fine.
The history of the 6.5x55mm Swedish Mauser is interesting. It was developed jointly in 1891 by Sweden and Norway and adopted as the official military cartridge of those nations in 1894. The Norwegians used it in the Krag-Jorgensen rifle and the Madsen machinegun.
The Swedes used Mausers, including the Models 94, 96, 35, and 31, as well as the Ah m/42 semiautomatic rifle. Ammunition from both countries was initially identical, but Sweden later changed the case dimensions slightly and loaded it to a higher pressure for use in their Mauser rifles.
This situation persisted until 1990, when Denmark, Norway, and Sweden standardized specifications, and the cartridge was officially renamed the "6.5x55 SCAN." (This is not to be confused with the "6.5x55 SKAN," an obscure cartridge with a very slightly longer case; it won't chamber in standard 6.5x55 rifles.) The European C.I.P. designation is "6,5x55 SE," while in the U.S., just about everyone calls it the 6.5x55 Swede.
Pressure limits for the 6.5x55mm Swedish have been a source of some confusion for American shooters for decades. Popular wisdom has it that the Mauser 94s and 96s are "significantly weaker" and must not be used with the heavier loads intended for "modern" bolt actions, such as the Mauser M98 and American-made Winchesters, Remingtons and Rugers.
Be that as it may, in Europe, the round is certified by C.I.P. at a maximum pressure of 55,114 psi, with proof loads listed at 125 percent of that, or 68,893 psi. All Swedish Mausers are proof tested (with one round) at 65,992 psi, and Swedish military ammunition was loaded to a modest 46,412 psi.
In the U.S., S.A.A.M.I. maximum pressure is listed as 51,000 psi, so all U.S. ammunition is completely safe in the Krag and M94 and 96 Mauser rifles, but it's seriously underpowered in modern sporters. Handloaders for these rifles can improve ballistics considerably (more on that later).
One outstanding attribute of 6.5mm cartridges is that they shoot long-for-caliber bullets. This is known in the trade as high sectional density. Such long, skinny bullets penetrate like the dickens, and rather straightly at that, so they end up where they're supposed to go: in the vitals. Couple that with a good controlled-expansion bullet, and the hunter has a recipe for success.
Nowadays, modern rifles chambered for the 6.5x55mm Swedish are relatively abundant. The Winchester Model 70 Featherweight, Ruger Model 77, and Remington Model 700 have recently been chambered for this fine old round, along with numerous imports like the excellent CZ Model 550 and Sako and Tikka bolt guns.
The rifle I used for this report is a limited-edition Remington Model 700 Classic that was produced in 1994. It has a 22-inch barrel with a 1:8 twist. The scope used for all my shooting results is a Meopta 3-9X 42mm.
Factory loads with the now-standard 140-grain bullets produced dismal accuracy in my rifle. However, I just knew I could get the rifle to shoot better with handloads.
A couple of quirks need to be considered when handloading the 6.5x55mm Swedish. First is pressure limits, which I addressed earlier. The dogmatic recommendation in most manuals to use milder loads in the Krag and Mauser 94 and 96 rifles to be on the safe side just makes sense.
Although Hornady used a Mauser M96 to develop its data, the manual states that maximum loads should be approached with care and cautions reloaders against "attempting high intensity loads in either the Mauser or Krag actions."
Speer takes a different approach. In Reloading Manual #14, Speer has two sets of 6.5x55mm Swedish data. One is labeled for "Military Actions," the other for "Strong Commercial Actions" that "approach pressures of 58,000 psi." This is in the same class as "6.5x55 ammunition loaded in Europe."
The second consideration is cartridge length. Recall that the original military ammo was loaded with long 156-grain bullets, so the chamber throats were correspondingly long to accommodate them. Since there are thousands of military rifles and a lot of surplus ammo out there, companies throat modern rifles the same old way.
This is fine and dandy when shooting long, heavy bullets, but not ideal when shooting lighter, shorter bullets.
When loaded to the lengths specified in the loading manuals, lighter bullets careen down that long throat until they hit the rifling. This does not help accuracy. Most all modern-day rifles chambered for the 6.5x55mm Swedish are made on what are called "long actions" (i.e., .30-06 length), and they have a correspondingly long magazine.
Therefore, it is no problem to seat bullets out closer to the rifling. Keep in mind, however, that doing so will increase pressures slightly over the same load with the bullet seated deeper. Benchrest shooters routinely seat bullets to just touch the rifling or maybe 0.010 inch off, as this usually gives the best accuracy. This approach is easy with the long magazines on modern-day 6.5x55mm Swedish rifles.
First, determine the length of a cartridge if the bullet was seated out to touch the lands. There are fancy tools for this, but I use a cleaning rod and a pencil. Call this the "0 COL" length. Subtract 0.010 inch from that, make up a dummy round to that length, and try it in the gun. It should chamber easily with no rifling marks on the bullet when ejected.
Then work up loads normally from the starting charges, checking for pressure signs. Watch your chronograph for unusually high velocities; this is a good indirect indication of high pressure.
I first tried the shorter lengths, but accuracy was pretty sad. My Remington Model 700 has the typical very long throat, so I tried seating the bullets out to miss the lands by 0.010 inch, and accuracy after that was outstanding. Only the 156- and 160-grain bullets were seated deeper.
As with any rimless case, one needs to use care in setting the sizing die so as not to push the shoulder back too much. From 0.002 to 0.003 inch is plenty, resulting in a slight "crush fit" when you close the bolt is perfect. This will help prevent incipient case head separations.
The 6.5x55mm Swedish case is slightly different from the almost-universal .30-06 family. The rim is 0.007 inch larger in diameter than the .30-06's, and it's slightly thicker (0.059 inch versus 0.049 inch), so a different shellholder is required. The 6.5x55mm Swedish's relatively small case calls for standard Large Rifle primers.
I tried 38 different loads, and with the current renewed interest in 6.5mm cartridges, there is a great selection of bullets from which to choose. I concentrated on bullets weighing from 120 to 140 grains along with a couple of the traditional 156- and 160-grain bullets.
I quickly learned that two powders are optimal for the 6.5x55mm Swedish. Either Hybrid 100V or IMR 4831 will do about anything you need to do with the cartridge, and if I had to pick one, it would be Hybrid 100V in a walk. It delivered high velocities and great accuracy with all bullets tested with it.
Take a peek at the chart. The short answer is to use 45.5 grains with 120-, 125-, and 129-grain bullets and 43.5 to 44.5 grains with 140-grainers.
Hornady roundnose bullets exude a smug air of authority in all calibers, and the 160-grain 6.5mm version closely mimics the 6.5x55mm Swedish's original military round. This long bullet doesn't lend itself to seating 0.010 inch off the lands, however, so I just seated it to the cannelure.Over 48.0 grains of H4831SC, groups averaged 0.83 inch at 2,471 fps, with a standard deviation (S.D.) of only 7. IMR 7828SSC also did well with this bullet.
While some may whine about its "poor ballistic shape," the fact is it is accurate and deadly and, with a sectional density of .328, will penetrate like crazy.
Another modern heavyweight for the 6.5x55mm Swedish is the Norma 156-grain Oryx Bonded bullet. It performed very well with the same charge of H4831SC, averaging 2,533 fps and 1.07 inches for accuracy.
It may have been designed for war, but these days the role of the 6.5x55mm Swedish Mauser is hunting. I had an exotics hunt in Texas scheduled for last December and was so pleased with the range performance of the 6.5x55mm Swedish that I took it south.
I was after a fallow buck, and my guide said there were some "nice" ones and some "exceptional" bucks on the ranch. I saw one buck early the second morning, but the guide described it as "nice" but "too small." Heck, he looked great to me, but I held my fire. By the evening of the last day of the hunt, I was kicking myself for not taking that buck. The vision of going home empty-handed loomed.
Then, promptly at 4:30, as if on cue, from my left a large deer with palmate antlers raced into the clearing I was watching and skidded to a stop. It was a fallow deer, with a beautiful chocolate coat and nice antlers.
It didn't take me long to unlimber my Model 700 and place a Hornady 129-grain SST in his shoulder. He collapsed immediately and never moved. It was the "nice" buck I had seen before, but I am quite proud of him. He is a beautiful representative of the species and will always be a good memory of a fine hunt. And the venison was delicious.
The 6.5x55mm Swedish has domesticated nicely and delivers impressive performance on the range and in the field. With today's modern rifles stoked with factory loads or carefully tailored handloads, the hunter is well equipped for just about any game.