Compared: 9.3x74R and .375 H&H Flanged Magnum

By Chuck Hawks

This is an interesting pair of cartridges. They were both designed around the beginning of the 20th Century and are rimmed cartridges intended for use in single shot and double-barreled rifles as well as drillings (three barreled combination rifle/shotguns). The .375 H&H Flanged is an English cartridge and the 9.3x74R is a German cartridge. Their appearance is similar. They are both based on extra long, rimmed cases with a lot of body taper and small shoulders. They were intended to be general purpose medium bore cartridges suitable for hunting heavy game and their factory loaded ballistics are quite similar. This cartridge comparison is therefore definitely "apples to apples."


As with other European cartridges, 9.3mm is the approximate caliber (actual bullet diameter is .366"), 74mm is the case length and the "R" stands for rimmed, which this case is. It was designed to replace the earlier 9.3x72R black powder number for use in single shot rifles, doubles and drillings and is still chambered in such rifles today. Its great overall length prevents the 9.3x74R from being adapted to bolt actions, but the ballistically identical and rimless 9.3x62 provides 9.3x74R ballistics in a shorter cartridge designed for use in repeating rifles.

The 9.3x74R has long been a European favorite for hunting bear, wild boar, red stag and Scandinavian moose. It is also popular in Africa, where it serves as an all-around medium bore caliber. Like the .375 Flanged Magnum, the 9.3x74R is less powerful than the .375 H&H Belted Magnum, but has been used for much the same purposes.

Factory loaded 9.3x74R ammunition is available from Stars & Stripes, A-Square, Norma, RWS, Sellier & Bellot and now Hornady, who added it to their loading list in 2007. Reloaders can get 9.3mm bullets from A-Square, Speer, Nosler, Barnes, Swift, Woodleigh and perhaps others. Common bullet weights include 232 grains, 250 grains, 270 grains, 286 grains and 300 grains. The more or less "standard" 9.3x74mm load for which most double rifles and drillings are regulated drives a 286 grain bullet at about 2360 fps. 286 grain bullets are commonly available in both soft point and solid (FMJ) form. The latter are traditionally chosen for use on dangerous CXP4 game, although most experts today would suggest something more powerful than the 9.3x74R for such use.

.375 Flanged Magnum

Holland & Holland introduced this rimmed cartridge in 1912 for use in H&H double barreled rifles, along with a belted rimless version of the cartridge that we call the .375 H&H Magnum. The latter was intended for use in bolt action rifles. It is quite common for European manufacturers to introduce rimmed (which the British call flanged) and rimless versions of the same cartridge. The belted .375 H&H became extremely popular around the world and is well known in North America. The flanged version of the .375 is less well known, almost obscure in the Americas, because we seldom use double rifles. As far as I know the only way to get a new rifle in .375 Flanged Magnum is to special order it from H&H or some other British "best gun" maker, which will cost tens of thousands of dollars and require a waiting period for delivery measured in years.

The performance of the .375 Flanged does not quite equal the performance of the .375 Belted because it is loaded to lower pressure to ease the extraction problem in break-open action rifles. Never the less, it is a powerful medium bore cartridge that has been successfully used on a wide variety of CXP3 and CXP4 game. Typical factory loads drive a 300 grain bullet at a MV of 2400 fps. Kynoch (UK) offers factory loads with 235 grain (at 2750 fps), 270 grain (at 2600 fps) and 300 grain (at 2425 fps) bullets. These Kynoch velocities were taken in 28" barrels, so velocities from normal 24" barrels will probably be lower. It is my understanding that Kynoch uses Woodleigh Weldcore bullets. They also sell components to reloaders.

In the U.S., Stars & Stripes Custom Ammunition offers .375 Flanged Magnum factory loads in their Safari line using the A-Square 300 grain Triad of bullets (Lion Load, Dead Tough and Solid) or 270 and 300 grain Woodleigh Weldcore bullets. Reloaders can use any of the .375" bullets commonly available for the .375 H&H Belted Magnum. .375 belted Magnum reloading data can be used for the flanged cartridge, but avoid maximum loads and stay with those that essentially replicate .375 Flanged factory velocities.

The comparison

In order to compare and evaluate these cartridges we will examine them in terms of velocity, energy, trajectory, bullet sectional density, bullet frontal area, killing power and recoil. At the end will be a summary of our findings.

These are cartridges primarily used in double rifles. Doubles must be regulated for a specific load in order to get both barrels to shoot to the same point of impact. For that reason, the hunter cannot change bullet weights willy-nilly as one can with a bolt action rifle. With a double you not only have to re-zero the sights for a new bullet weight, but also re-regulate the barrels. The latter is a task that should not be embarked upon lightly, even with a rifle that is allegedly "user adjustable." Consequently, for this comparison we are going to select one representative load for each caliber.

Our comparison load for the 9.3x74R will use an A-Square 286 grain round nose (RN) bullet at a MV of 2360 fps as factory loaded by Stars & Stripes and A-Square. Our selected load for the .375 Flanged Magnum will use an A-Square 300 grain RN bullet at a MV of 2400 fps, which can be had in Stars and Stripes factory loads. These are essentially "standard" loads for their respective calibers and can easily be duplicated by reloaders.


Velocity may or may not directly affect killing power, but for sure it is the most important factory in computing kinetic energy. It is also crucial to the bullet's trajectory. Here are the velocities in feet-per-second of our comparison loads at the muzzle, 100 and 200 yards, the latter being considered extreme range for a double rifle.

  • 9.3x74R, 286 gr. RN - 2360 MV, 2089 at 100 yards, 1844 fps at 200 yards
  • .375 Flanged, 300 gr. RN - 2400 fps MV, 2116 fps at 100 yards, 1852 fps at 200 yards

As can be seen from those numbers, the .375 starts 40 fps faster and maintains a slim 27 fps advantage at 100 yards. By 200 yards the difference is down to 8 fps, which is negligible.

Kinetic Energy

Energy is the ability to do work. In the case of a hunting rifle bullet, energy powers penetration and bullet expansion, very important factors in killing power. Here are the energy figures for our representative loads, expressed in foot-pounds.

  • 9.3x74R, 286 gr. RN - 3538 ft. lbs. ME, 2771 ft. lbs. at 100 yards, 2157 ft. lbs. at 200 yards
  • .375 Flanged, 300 gr. RN - 3837 ft. lbs. ME, 2983 ft. lbs. at 100 yards, 2284 ft. lbs. at 200 yards

Here, although both are powerful cartridges, the difference is more noticeable. In energy the .375 Flanged has a clear advantage over the 9.3x74R. The .375's advantage results from the its heavier as well as slightly faster bullet.


Trajectory matters because the more a bullet drops the harder it is to place it precisely at extended ranges. Doubles are short range rifles, normally used within 150 yards, so with double rifles and their cartridges, trajectory is less important than it would be for a long range rifle. Here are the figures, computed for a line of sight 0.8" above the bore line and zeroed at 100 yards, reasonable assumptions for a double rifle used with iron sights.

  • 9.3x74R, 286 gr. RN - +0.5" at 50 yards, 0 at 100 yards, -2.5" at 150 yards, -7.3" at 200 yards
  • .375 Flanged, 300 gr. RN - +0.5" at 50 yards, 0 at 100 yards, -2.4" at 150 yards, -7.0" at 200 yards

As can be gathered from these numbers, the difference in trajectory between the two cartridges is inconsequential.

Sectional Density

The sectional density (SD) of bullets is calculated by dividing a bullet's weight (in pounds) by the square of its diameter (in inches). A heavier bullet of any given caliber will have greater sectional density than a lighter bullet of the same caliber. If you compare bullets of different calibers, as we are doing here, the larger caliber's bullet will have to be heavier to match the SD of the smaller caliber bullet.

Sectional density is important because, given bullets of identical design at identical velocity, the bullet with the greatest SD will penetrate the deepest. The deeper the wound channel (of any given diameter) the more tissue is destroyed and the greater the killing power. Probably the most intelligent way to compare rifle bullets is based on SD rather than weight. Here are the SD numbers for our selected bullet weights.

  • 9.3x74R, 286 gr. - SD .305
  • .375 Flanged, 300 gr. - SD .305

The SD of our selected calibers and bullet weights is identical. Neither has an advantage in SD. Medium bore bullets with a SD of about .250 or better have proven adequate for all thin-skinned game, including the great bears and big cats, worldwide. Bullets with a SD in excess of .300 are regarded as the most suitable choice for CXP4 game. The excellent .305 SD of the 9.3mm/286 grain and .375/300 grain bullets is the primary reason why these cartridges have such good reputations on large and heavy game.

Cross-sectional Area

Bullet cross-sectional (frontal) area is important because the wider the wound cavity (of any given depth), the more tissue is destroyed and the greater the killing power. Bullet cross-sectional area is independent of bullet weight. (A 150 grain .30 caliber bullet is the same diameter as a 220 grain .30 caliber bullet.) The actual diameter of a 9.3mm bullet is .366" and the diameter of a .375 Mag. bullet is .375". Here are the bullet cross-sectional areas in square inches.

  • 9.3mm - .1052 sq. in.
  • .375" - .1104 sq. in.

The .375 has an undeniable advantage in cross-sectional area. This will serve to enhance its killing power, as we shall see next.

OGW Killing Power

Killing power is difficult to quantify due to the mass of variables, not the least of which are the game animal's state of mind when shot and the effect of bullet expansion on the wound channel. Those facts notwithstanding, many gun writers and sundry authorities have tried to devise formulas to estimate the killing power of rifle bullets. In my opinion, one of the best attempts is the "Optimum Game Weight Formula" devised by Edward A. Matunas. It attempts to take into consideration at least some of the various quantifiable factors affecting killing power without trying to prove some special theory about bullet weight, caliber, or velocity. Best of all, it relates killing power to distance and animal weight.

The results of Optimum Game Weight (OGW) are expressed in terms of the range and live animal weight for which a given cartridge is optimum. There is an extensive OGW table on the Tables, Charts and Lists Page of Guns and Shooting Online. Here are OGW figures for our two cartridges.

  • 9.3x74R, 286 gr. RN - 1333 lbs. at 50 yards, 1094 lbs. at 100 yards, 893 lbs. at 150 yards, 726 lbs. at 200 yards
  • .375 Flanged, 300 gr. RN - 1550 lbs. at 50 yards, 1279 lbs. at 100 yards, 1050 lbs. at 150 yards, 857 lbs. at 200 yards

These numbers speak for themselves. Both are very powerful cartridges, suitable for 1000 pound beasts over 100 yards away. However, the .375's slightly heavier bullet at slightly higher velocity pays dividends in OGW killing power and moves it ahead of the 9.3x74R in this category.


Recoil is the price that we must pay for shooting powerful rifles. Neither of these cartridges are soft shooters, but the .375 Flanged Mag. definitely kicks harder than the 9.3x74R in rifles of equal weight. The .375 burns more powder and drives its heavier bullet at higher velocity, all factors that contribute significantly to recoil energy (how hard the rifle comes back) and recoil velocity (how fast it comes back). There are no welfare benefits in the laws of physics.

Here are the recoil energy (in foot pounds) and velocity (in feet-per-second) figures taken in 9 pound rifles.

  • 9.3x74R, 286 gr. at 2360 fps - recoil energy = 30.6 ft. lbs.; recoil velocity = 14.8 fps
  • .375 Flanged, 300 gr. at 2400 fps - recoil energy = 34.4 ft. lbs.; recoil velocity = 15.7 fps

Recoil is bane of the medium bore calibers. Both of our calibers come back at the shooter fast and hard. However, there is a difference and that difference might be important to some shooters. The truth is than anyone can shoot more accurately with a rifle that kicks less, and bullet placement is, by far, the most important factor in killing power. Lower recoil is the 9.3x74R's advantage over the .375 Flanged.

Summary and Conclusion

These are both very powerful medium bore cartridges that have earned an enviable reputation in hunting fields around the world. The .375 Flanged Magnum holds a slight performance advantage over the 9.3x74R, primarily in the areas of kinetic energy and cross-sectional area. The bottom line of this is exemplified by its 185 pound advantage in OGW killing power at 100 yards. On the other hand, the 9.3x74 kicks less and is available in production double rifles that, while expensive, are far less so than the very few custom built British doubles available in .375 Flanged.

These production doubles do not require an extended waiting period for delivery. A Merkel Petite Frame Double Rifle in 9.3x74R, for example, can be shipped from stock in the Merkel USA warehouse directly to your dealer in a matter of days. This relative availability might be crucially important to the North American hunter that books his Alaskan brown bear and moose hunt or African safari weeks or months, rather than years, in advance. 9.3x74R ammunition is also less expensive and more available than .375 Flanged ammunition. Sometimes 3538 ft. lbs. of energy in the hand is better than 3837 ft. lbs. on order.

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Copyright 2007, 2012 by Chuck Hawks. All rights reserved.