Otto Bock's 9.3x62mm Cartridge Historical Review

I readily admit to liking a number of odd-metric cartridges. This extends to hunting cartridges and when it comes to medium bores, one of my favorites happens to be the hard-hitting, yet surprisingly accurate 9.3x62mm Mauser. The 9.3x62mm is a classic old sporting cartridge introduced by German gunsmith Otto Bock at the dawn of the 20th Century in 1905. The cartridge was designed for general purpose use, being suitable for hunting the larger species in not only Europe and North America but also Africa. In 1905, Germany was an empire with colonies in Africa and China. While the 8x57mm Mauser was a fine military cartridge, it had proven to be a bit light in Africa. Bock recognized this. He also understood the value of a hard-hitting cartridge that would fit into a standard 1898 Mauser action. So, he designed his new 9.3mm cartridge to fit into a standard 1898 Mauser action needing only a barrel swap. This aided its popularity when it was first introduced. African hunters and settlers typically chose military rifles for their economical nature and durability.

The cartridge Bock developed is a rimless bottleneck design. There is no weird belt or anything odd about it. Instead, it is very straightforward design with a 3.291-inch (83.6mm) overall length allowing it to feed from a standard 1898 Mauser magazine. Rim diameter is 0.470 inch (11.95mm), the same as an 8x57mm Mauser, so no changes were needed to a 1898 Mauser bolt. Bullet diameter is 0.366-inch, so a noticeable step up in payload over an 8x57mm Mauser, but without the recoil of the big bores. It should also be remembered that some governments banned civilian use of military calibers, due to fear of rebellions and assorted unpleasantries. However, as the 9.3x62mm was never a military cartridge there were no issues. What about performance? The original load drove a 0.366-inch 285-grain bullet at 2,150 fps. In the years following World War I though, some ammunition manufacturers upped the velocity to around 2,400 fps. The increase in velocity had a useful effect on the performance of these heavy projectiles with their high sectional density. In addition, loads with lighter weight bullets were introduced to increase the versatility of the cartridge. A number of companies loaded 9.3x62mm ammunition and it quickly became quite popular in both Europe and Africa. Even Kynoch of England loaded Bock’s cartridge and marketed it as the 9.3mm Mauser.

Over a century after its introduction, the 9.3x62mm remains a very popular hunting cartridge. A 285-grain bullet, driven at 2,362 fps generates 3,543 ft-lbs. of energy at the muzzle (compare that to 196-grain 8x57mm Mauser, traveling at 2,357 fps with 2,417 ft-lbs. of energy fired out of a 23.6-inch barrel). It has proven to be an excellent cartridge for game such as eland, zebra, giraffe and wildebeest. Make no mistake though, Bock’s 9.3x62mm has also cleanly taken every dangerous species on the Dark Continent as well. Though, of a smaller bore than the legal minimum for dangerous game in most countries, 0.366 VS 0.375 inch, many specifically make an exception for it. So, in many African countries today the bottom limit for dangerous game is not the .375 but rather the 9.3x62mm.  In Europe, the 9.3x62mm is very popular for game such as moose. It also has a following in Canada where it is capable of tackling anything, including the great bears. Here in the US, ammunition, reloading components, dies and data are all readily available. Most loads typically run in weight from 250 to 286 grains. What is also interesting is the 9.3x62mm performs quite well out to about 300 yards. While recoil is attention getting, it is not obnoxious like some of the bigger bores.

To find out how well the 9.3x62mm Mauser cartridge would perform today, I selected five modern loads for testing. These ranged in weight from 250 to 286 grains. Test rifle was my CZ-USA CZ 550 FS. This has a Mannlicher-style stock which extends to the muzzle and a 20.5-inch barrel. Test ammunition consisted of Nosler’s 250-grain AccuBond, Lapua’s 285-grain Mega Soft Point, Federal’s 286-grain Woodleight Hydro Solid, Nosler’s 286-grain Partition and their 286-grain Solid. Four five-shot groups were fired from a bench with a rear bag with each load with velocity readings measured using a Labradar Doppler radar chronograph. As I was shooting five-shot groups from a light sporter, I let the barrel cool down between each group. Cartridges fed smoothly, chambered easily, and the bolt operated with little effort. I fired all groups using the set feature of the CZ set trigger. The trigger was wonderful when used in this manner, simply fabulous. Recoil, bark, and blast of the 9.3x62mm was attention getting. I wore my old High Power shooting coat and was never truly bothered by the recoil. The muzzle blast played havoc with my LabRadar though.

I knew it was going to be a good day when the Mannlicher stocked CZ 550 FS plunked the first five rounds of Nosler’s 250-grain AccuBond load into just 0.8 inch at 100 yards. Bock’s old 1905 vintage big game medium bore certainly proved capable of fine accuracy.  As the day wore on, Federal’s 286-grain Woodleigh Hydro Solid averaged 0.8 inch at 2,284 fps. Lapua’s 285-grain Mega SP averaged a similar 0.8 of an inch at 2,229 fps. Nosler’s 250-grain AccuBond averaged 0.9 of an inch at 2,365 fps, while their 286-grain Partition and 286-grain Solid both averaged 1.2 inches. If my velocities look a bit low, keep in mind the short 20.5-inch barrel. Next, I extended the range and engaged steel targets placed at 200 and 300 yards. As to be expected, the 9.3x62mm slapped the steel hard. The CZ had zero issues connecting at 200 and 300 yards and showed its ability to reach out if needed. All I had to do was break the shot correctly and the CZ tagged the 300 yard steel plate. I came away quite pleased with the performance of the 9.3x62mm cartridge. It would be good medicine for black or brown bear as well as moose here in North America. An old European classic, Otto Bock’s 9.3x62mm cartridge is capable of fine accuracy while delivering a heavy payload on target. It is one of my favorites and a cartridge I recommend considering.

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