Compared: .338-06 A-Square, .35 Whelen and 9.3x62mm Mauser
By Chuck Hawks
These three powerful medium bore cartridges are all based on cases of very similar size, and they all use the same 17.5 degree shoulder angle. In fact, the .338-06 A-Square and .35 Whelen are based on the same case, a necked-up .30-06. The 9.3x62 case is very similar to the .30-06 case, and handloaders can form 9.3x62 brass from .35 Whelen cases with one pass through an RCBS sizer die.
Although the case capacity of these three cartridges is practically identical, they use bullets of different diameter. The .338-06 uses .33 caliber bullets, the .35 Whelen uses .35 caliber bullets, and the 9.3x62 uses bullets of .36 caliber. That and the various maximum average pressures (MAP) specified by SAAMI and CIP are what create the differences between these three cartridges and makes this comparison worthwhile. (All three of these cartridges are covered in detail in individual articles that can be found on the Rifle Information Page.)
The .338-06 A-Square
Wildcatters have been necking-up .30-06 cases to accept .33 caliber bullets since at least 1945. The .333 OKH, heavily promoted by the late Elmer Keith, is a prime example. But it was the introduction of a wide range of .338" bullets for reloading the .338 Win. Mag. in the late 1950's and early 1960's that breathed new life into the .33-06 cartridge and allowed it to prosper as the .338-06. From that point on the .338-06 became one of the most popular wildcats.
A-Square finally legitimized the .338-06 by standardizing it as a SAAMI cartridge in 1998 and Weatherby and A-Square supply rifles and factory loaded ammunition in the caliber. Stars and Stripes is another source of .338-06 factory loads.
The .338-06 is a powerful cartridge, suitable for all large and dangerous North American big game with proper bullets. It would also be a good choice for hunting African plains game. Although overshadowed by the more powerful .338 Winchester Magnum, the .338-06 will accomplish pretty much the same tasks within its maximum point blank range (MPBR).
A-Square .338-06 factory loads are available with a 200 grain Nosler Ballistic Tip bullet at a MV of 2750 fps, a 250 grain SP boat-tail at 2500 fps, and a 250 grain RN Dead Tough bullet at 2500 fps. The sole Weatherby factory load uses the 210 grain Nosler Partition bullet at a MV of 2750 fps.
The .35 Whelen, named for gun writer Townsend Whelen, dates back to the early 1920's and enjoyed a long run as a successful wildcat. The .35 Whelen was originally intended to fill the gap between the .30-06 and .375 H&H. Unlike the long .375 H&H, the .35 Whelen is a .30-06 length cartridge and works in standard length rifle actions, its primary claim to fame. It is an excellent medium range cartridge for all North American big game and enjoys a good reputation as an elk and moose cartridge.
Remington finally standardized the .35 Whelen in 1987. Remington offers rifles and Federal, Remington, and Stars and Stripes offer factory loaded ammunition. Federal lists a 225 grain factory load. Stars & Stripes offers production factory loads with 200, 225, and 250 grain bullets, and Remington catalogs .35 Whelen factory loads with a 200 Core-Lokt Pointed Soft Point (PSP) bullet at a MV of 2675 fps and a 250 grain PSP bullet at a MV of 2400 fps.
This cartridge was developed in Germany by noted gunsmith Otto Bock around 1905, primarily for use on African big game. I suspect that he used a .30-03 case trimmed to 62mm as the basis for his creation, but do not know that for a fact.
However it was designed, the 9.3x62 became a very successful cartridge among European big game hunters. The fact that, by design, it worked fine in standard length Mauser 98 actions was a great boon to the acceptance of the cartridge. Many fine bolt action rifles in 9.3x62 were turned out, and production rifles in the caliber are still offered. In the days of the various European colonial empires the 9.3x62 was widely employed in Africa, and still is.
Most of the ex-British colonies in sub-Saharan Africa have legislated .375 as the minimum caliber for shooting CXP4 dangerous game, but generally the African countries that were once colonies of Continental European powers allow the 9.3x62 to be used on such game. As such, it is the caliber with the least recoil officially recognized as suitable for the purpose.
Factory loaded ammunition is provided in the US by A-Square, Sellier & Bellot, and Norma. Bullets for reloaders are available from Speer, Barnes, Swift, Woodleigh, and Nosler, so even though the cartridge is not popular in North America, shooters with 9.3x62mm rifles are reasonably well provided for.
Bullet weights typically range from 232 to 286 grains, with the 286 grain bullet being the most popular and the weight that made the caliber's reputation on heavy African game. American reloaders will find that the relatively flat shooting 250 grain bullets are suitable for both CXP2 and CXP3 game, and the 270 and 286 grain bullets are suitable for all large and/or dangerous North American big game.
There are enough different factory loaded bullets to make selecting truly representative loads for these three cartridges problematic. To try and eliminate some of the variables we are going to use representative reloads with heavy bullets at factory load velocities. That will allow us to use the same design of bullet in each caliber, in this case Nosler Partition spitzer bullets, which are available in all three calibers. (Stars and Stripes can, in fact, provide new factory loaded ammunition with Nosler Partitions in all three calibers.) These bullets have a similar form and will make our comparison more uniform.
Here are our selected full power (factory equivalent) loads:
While we are at it, let's also compare a trio of medium power reloads. Loads that a reloader who wants sufficient power to harvest North American CXP3 game without excessively punishing recoil might choose. In the interests of reasonably flat trajectory, let's set the muzzle velocity for these loads at 2400 fps in order to retain a reasonably flat trajectory, and bullet sectional density at no less than .250 to retain reasonable penetration in large animals like elk.
Here are our selected medium power handloads, also using available Nosler bullets:
We will compare our three cartridges with those loads and bullets in terms of ballistic coefficient (BC) and sectional density (SD), velocity, energy, trajectory, killing power, and recoil. At the end of the article we will summarize, and conclude with final comments. So, let's get started!
Ballistic coefficient and sectional density
Ballistic coefficient is defined as the ratio of a bullet's sectional density to its coefficient of form. BC represents how well a bullet flies through the air. A higher BC helps a bullet retain more of its initial velocity and energy down range and also results in a flatter trajectory.
Sectional density is defined as a bullet's weight (in pounds) divided by the square of its diameter (in inches). It is important because, other factors being equal, the higher its SD the deeper a bullet will penetrate. Shape (round nose or pointed) has no affect on SD, just the bullet's mass and diameter. Penetration is an important factor in the length of the wound channel, and the amount of tissue disrupted. Clearly, a bullet must penetrate to the vitals to disrupt vital function.
Here are the published ballistic coefficients and sectional densities for the bullets used in the loads compared in this article:
Those numbers show that these bullets are reasonably similar in BC. The .358 bullets trail slightly because their SD is lower, and that is a component in calculating BC.
A more significant advantage for the .338 and 9.3mm bullets lies in their superior sectional densities. A SD of .279 (best case for the .35 Whelen) is sufficient for adequate penetration in all CXP3 game, given proper bullet design and shot placement. That includes the largest and most dangerous types, such as polar bear. It is, however, a bit low for use on thick-skinned dangerous game such as buffalo and elephant, where SD's of at least .300 are recommended.
Bullet frontal area
The fatter a bullet is the bigger the wound cavity it is likely to make and the more tissue it destroys as it penetrates. So bullet cross-sectional area is an important factor in wound ballistics. The actual diameter of .338-06 bullets is .338", the actual diameter of .35 Whelen bullets is .358", and the actual diameter of 9.3x62mm bullets is .366". All bullets of a given diameter (caliber) have the same cross-sectional area regardless of shape or weight.
Here are the bullet cross-sectional areas for our three calibers (in square inches):
As can be seen, the .35 Whelen and 9.3x62 have a marked advantage in cross-sectional area. The .35 Whelen's advantage in frontal area over the .338-06 will tend to be offset in the real world the .338 bullet's superior SD, since both use 250 grain bullets in our full power loads and 225 grain bullets in our medium velocity loads. Other things being equal, the .338-06/250 will create a longer wound channel while the .35 Whelen/250 will make a larger diameter wound channel. (Ditto if you compare 225 grain bullets in those two calibers.)
The 9.3x62/286 bullet has both the best frontal area and good SD. This bullet will tend to create the biggest wound cavity if it is carrying enough energy to power adequate expansion and penetration when it impacts a game animal.
Velocity is the most important component of energy and also decreases bullet flight time and hence flattens trajectory and reduces wind drift. A cartridge that shoots flatter is easier to hit with as ranges increase.
Here are the velocities from the muzzle (MV) to 300 yards in feet per second for our full power loads:
And here are the velocities for our medium power loads:
Note that the ballistically superior Nosler Ballistic Tip bullet retains its velocity somewhat more efficiently that the Nosler Partition bullets.
Kinetic energy is a measure of the ability to do work. It is energy that powers a bullet's expansion and penetration in a game animal. Bullet penetration and expansion are very important factors in killing power.
Here are the energy figures in foot pounds for our selected maximum loads from the muzzle (ME) to 300 yards:
And here are the energy figures for our medium power loads:
If, as is sometimes stated, approximately 1200 ft. lbs. of kinetic energy is required at bullet impact to make a reliable elk load, then all of the loads above, full and medium power, easily exceed that requirement to well beyond 300 yards.
Trajectory is important because the flatter a bullet shoots the less the shooter needs to compensate for bullet drop as ranges increase. The following trajectories, shown in inches above or below the line of sight at 100, 200, and 300 yards, are computed for the maximum point blank range (MPBR) +/- 3" of each load and assume an optical sight mounted 1.5" over bore.
Here are the trajectories of our full power loads:
The MPBR of our full power .338-06 load is 250 yards, the MPBR of the .35 Whelen is 240 yards, and the MPBR of the 9.3x62 is 238 yards. Those are the distances at which the bullet drops 3" below the line of sight, having been allowed to rise 3" above the line of sight at the peak of its arc. Within those distances you can hold right on the heart/lung area of any big game animal without having to hold over or worry about bullet drop. The full power, factory load equivalent .338-06 A-Square is the flattest shooting cartridge in our comparison, although only by a modest amount.
Here are the trajectories of our medium loads:
The MPBR of our medium power .338-06 load is 240 yards, the MPBR of the .35 Whelen is 239 yards, and the MPBR of the 9.3x62 is 242 yards. There really isn't a great deal of difference in the trajectories of any of the six loads compared here. We here at Guns and Shooting Online do not recommend shooting at game animals beyond the MPBR of the cartridge, since proper bullet placement is required for quick kills regardless of the power of the cartridge.
Killing power is nearly impossible to calculate with certainty due to the great number of variables, not the least of which are the game animal's mental and physical condition when hit and the effect of bullet expansion on the length and diameter of the wound channel. And the most important factor, by far, in killing power is bullet placement.
That said, some method of estimating killing power could be a useful tool in cartridge comparisons and load selection. In my opinion, one of the best attempts to estimate killing power on game animals is the "Optimum Game Weight Formula" devised by Edward A. Matunas. It at least attempts to consider more than one factor and relates the result to the live weight of the animal and the distance at which it is shot. OGW assumes proper bullet placement with the correct design of bullet for the job.
Fortunately, OGW seems to have a positive correlation with results in the field. (There is an extensive OGW table on the Tables, Charts and Lists Page of Guns and Shooting Online.)
Here are the Optimum Game Weight numbers (in pounds) for our maximum loads at the muzzle, 100, 200, and 300 yards:
Here are the OGW numbers for our medium power loads:
These are, across the board, high OGW's. The average adult male lion weighs about 350 pounds, average Rocky Mt. bull elk about 500 pounds, North American bull moose about 600-1000 pounds, adult male grizzly/brown bear about 700 pounds, polar bear about 900 pounds, Cape buffalo about 1000 pounds, and the average adult male American bison or Asian water buffalo about 1600 pounds.
All three cartridges are adequate to well beyond 200 yards for shooting heavy CXP3 game such as elk, even with medium power loads. Dangerous CXP3 game, such as lion and the great bears, should not be shot beyond the sure kill range of the hunter in the field when under stress, usually estimated at not more than 150 yards and usually less, which distance is also within the OGW capability of all three cartridges, especially when using recommended full power loads.
Only for dangerous CXP4 game such as the various bovines do these cartridges become marginal, even with full power loads. The .35 Whelen is automatically suspect due to the inferior SD of its 250 grain bullet. The .338-06 and 9.3x62, combine bullets of good SD with adequate OGW numbers for Cape buffalo out to at least 100 yards. This pretty well reflects experience in the field, especially with the 9.3x62. The .338-06 is not a legal caliber for use on buffalo in most African countries and has not been widely used there, so there is little historical record to which to refer. All three calibers have been used successfully, although not extensively, on North American bison within 100 yards.
To compute recoil you need to know the rifle weight, bullet weight, MV, and the weight of the powder charge. Such computations are approximate, but adequate for our (comparative) purposes.
Here are the recoil energy (in foot pounds) and velocity (in feet per second) figures for our full power loads when fired in 8.5 pound rifles:
Here are the recoil figures for our medium power loads, also fired in 8.5 pound rifles:
Lower recoil is a big help in achieving proper bullet placement, as everyone can shoot more accurately with a rifle that kicks less, so our medium power reloads have the advantage here. If, as commonly generalized, the average shooter and hunter simply cannot withstand repeated recoil energy in excess of 20 ft. lbs., then all three of these cartridges are apt to promote flinching, especially with full power loads. I am inclined to believe that because I have seen it work out that way so often at the rifle range. Cartridges as or more powerful that the .30-06 tend to produce flinches, especially in lightweight rifles.
Still, there are clearly recoil differences between our three cartridges when shooting full power loads, and they favor the .35 Whelen. If the shooter in question must rely on factory loaded ammunition, the .35 Whelen is a good choice in terms of recoil. (And also in terms of the widespread availability of factory loads.)
With a medium power load the .338-06 can slip below the .35 Whelen (barely), but even with a medium power load the 9.3x62 kicks slightly harder than the .35 Whelen with a full power load. Among the cartridges in this comparison, the 9.3x62 is a particularly poor choice for the recoil sensitive shooter. High energy and killing power downrange bring with them the attendant penalty of high recoil.
None of these calibers are popular, but of the three the .35 Whelen is the most widely distributed in North America in terms of both rifles and ammunition. In Europe and Africa the 9.3x62 is the most popular caliber among our three contenders.
That is an important factor, in many cases the deciding factor, when choosing a rifle and cartridge. A hunter, for example, choosing a medium bore for an Alaskan hunt might reasonably pick the .35 Whelen, while a hunter booking an African safari might be well advised to go with the 9.3x62.
The .338-06 A-Square compares well in most categories and undoubtedly deserves more popularity than it has so far garnered. For the reloader the .338-06 is an excellent choice, as the case is easily formed from .30-06 brass, which is plentiful and relatively inexpensive. Also, there are more .338 bullets available than for either of the other calibers, and reloading data is included in most manuals.
While on the subject of reloading, there are more .358 bullets than .366 bullets marketed to reloaders, at least in North America, and practically all reloading manuals include the .35 Whelen. In Europe that situation would probably be reversed.
Based purely on ballistic performance, the 9.3x62 is probably the winner of this comparison, especially for European and African hunters. Add recoil to the mix and the .35 Whelen looks pretty good (if any of these cartridges can be described as "good" in terms of recoil), especially for North American hunters. For the reloader the .338-06 would be an excellent choice, and it scores well in all categories. These are all effective medium bore cartridges.
Copyright 2007, 2012 by Chuck Hawks. All rights reserved.