The .338-06 A-Square, .35 Whelen, and 9.3x62mm Mauser:
Under-appreciated Medium Bore Powerhouses
by Gary Zinn
As far as the vast majority of American shooters and hunters are concerned, most powerful, high-intensity, medium bore commercial rifle cartridges might as well be enrolled in a witness protection program. The only notable exceptions to this obscurity are the .338 Winchester Mag. and.375 H&H Mag., plus (arguably) the .338 Lapua Mag. Three under-appreciated medium bore cartridges are the focus of this article. None are labeled as magnums, yet all are more than powerful enough for hunting all CXP Class 3 game, and they even have enough terminal power to take on Class 4 game under certain conditions.
Briefly, key case and cartridge specifications and other relevant facts are as follows.
.338-06 A-Square: rim dia. .473”, max. case length 2.494”, max. COL 3.340”, bullet dia. .338”; MAP 53,000 cup; standardized in 1998
.35 Whelen: rim dia. .473”, max. case length 2.494”, max. COL 3.340”, bullet dia. .358”; MAP 52,000 cup; standardized in 1987
9.3x62mm Mauser: rim dia. .468”-.473”, max. case length 2.441”, max. COL 3.291”, bullet dia. 366”; MAP 390.0 OMPa (56,565 psi); developed/introduced circa 1905
The .338-06 and .35 Whelen had a long history as wildcats (formed by necking-up
.30-06 Springfield cases) before they were standardized as commercial cartridges. The 9.3x62, an original design, was a commercial sporting cartridge from its inception. (Critical case dimensions for the 9.3x62 are so close to those of the .30-06 that 9.3x62 cases may be formed from .30-06 cases.)
History and commercial viability
The 9.3x62 cartridge was designed to fit into the popular Mauser 98 bolt action rifle, and gained widespread favor among European and African big game hunters. One gets the impression that the 9.3x62 was to African settlers and hunters what the .30-30 Winchester and 6.5x55 SE were to North American and Scandinavian outdoorsmen, respectively — a no-nonsense cartridge that got the job done when hunting game for subsistence or sport in those parts of the world.
However popular it may have been and is still in Africa and Europe, the 9.3x62 is seldom seen in North America. As I write this in 2019, MidwayUSA catalogs only ten factory loads for the cartridge on its website, and I cannot find any listings of new production rifles available to American buyers.
The story of how the .35 Whelen originated is somewhat murky. Colonel Townsend Whelen, commanding officer of the Frankford Arsenal at the time, may or may not have conceived the idea of creating a .35 caliber cartridge by reworking the .30-06 case. It seems clear that James V. Howe, machine shop foreman at Frankford Arsenal, made the dies, reamers, and chambering tools for the cartridge, and built the first rifles. This happened in the early 1920s. (Mr. Howe cofounded Griffin & Howe, a maker of custom firearms that is still in business.)
Whatever Colonel Townsend’s role in developing the cartridge may have been, it has always borne his name. The .35 Whelen was a favorite chambering in Griffin & Howe custom rifles for decades, in effect making it a proprietary cartridge of the firm. Remington Arms sponsored the standardization of the cartridge in 1987.
Currently, the accessibility of the .35 Whelen is almost exactly like that for the 9.3x62; i.e., ten cartridge loads listed on MidwayUSA and no new production rifles readily available. Remington, Kimber, Ruger, and perhaps a couple others have sporadically produced limited numbers of .35 Whelen rifles, but no production of new factory rifles is ongoing in 2019, to my knowledge.
Little is certain about the history of the .338-06 as a wildcat cartridge, but it would be reasonable to speculate that it, like the .35 Whelen, has been around since the 1920s. No rifle or ammunition firm took an interest in promoting the cartridge for many years, until the A-Square munitions company sponsored its commercialization (along with the 6.5mm-06 cartridge). This happened circa 1998, but the A-Square company went out of business in 2012, which left both cartridges orphaned.
Currently there is no regular production of rifles in either of these calibers, no factory ammo being made for the 6.5mm-06, and very limited production of ammunition for the .338-06.
So why am I even writing about such moribund cartridges? Because they are legitimate options for a hunter who wants a knock-their-socks-off medium bore rifle, without having to tolerate quite the sound and fury (muzzle blast and recoil) associated with the medium bore magnums. The problem of laying hands on a rifle and hunting ammo is solvable, as I will discuss below.
Performance of selected loads
Fortunately, there are factory loads for each of these cartridges that nicely illustrate their ballistic capabilities. Here are the loads I will use for these illustrations.
.338-06: Nosler Custom 225 grain Partition — MV 2600 fps, BC .454, SD .281
.35 Whelen: Nosler Custom 250 grain Partition — MV 2550 fps, BC .446, SD .279
9.3x62: Hornady Custom 286 grain IL-RP — MV 2360 fps, BC .400, SD .305
I will evaluate these loads in terms of their maximum point blank range and bullet trajectory, velocity and energy, sectional density, killing power, and recoil.
+/- 3-inch MPBR, Far Zero, Trajectory
I am a firm believer in sighting-in hunting rifles and loads for maximum point blank range. My argument is that a prudent and responsible hunter should never attempt a shot at a game animal beyond the MPBR of the cartridge/load being used (and closer is always better). A case can be made that the +/- 3” MPBR I use is a bit restrictive for Class 3 and Class 4 size animals, and if one wants to use a larger +/- range that is okay. I use the +/- 3” zone for all big game cartridges and loads for global consistency when comparing effective ranges.
Trajectory matters, because the flatter a bullet flies the easier it is to hit a target down range. Bullet placement is the most important factor in achieving quick, humane kills, so anything that makes hitting easier is desirable.
The first number for each load is its MPBR yardage, rounded to the nearest 5 yard increment; the second is the far zero yardage associated with the MPBR. Trajectory is noted at 100, 200, MPBR (nearest five yard increment) and 300 yards (for a rifle sighted-in for a +/- 3 inch MPBR, computed for a scope mounted 1.5 inches over the bore). Trajectories are rounded to one decimal place; yardage is noted in parentheses. Results are in descending order of MPBR.
.338-06 225 grain load: 255 / 219 yards
Trajectory: +2.8” (100), +1.1” (200), -2.8“ (255), -7.6” (300)
.35 Whelen 250 grain load: 250 / 215 yards
Trajectory: +2.8” (100), +0.9” (200), -2.8“ (250), -8.4” (300)
9.3x62 286 grain load: 230 / 197 yards
Trajectory: +2.9” (100), -0.2” (200), -2.8“ (230), -12.4” (300)
Despite what some shooting/hunting writers and video makers would want you to believe, the vast majority of game animals, whatever the species, size, or locale, are taken well within the MPBRs of these three cartridges.
The most significant thing about these numbers is that trajectory of all loads deteriorates quickly at ranges beyond about 200 yards, with bullet drop at 300 yards considerably more than between far zero and MPBR distance, for all loads. This means that holdover would be required for shots much beyond the MPBR distance for which a rifle is sighted-in. This on-the-fly sighting adjustment is not conducive to optimal shot placement under field conditions and when adrenaline is pumping due to having a rare trophy in the sights.
Velocity and Energy
Velocity flattens trajectory and makes hitting easier as the range increases. It is also the most important factor when computing kinetic energy. Energy is a measure of the work a bullet can do, which in this case means powering bullet penetration and expansion. Energy is an important component of killing power, as will be discussed below.
Here are the velocity in feet-per-second (fps) and energy in foot-pounds (ft.lbs.) figures for our comparison loads at the muzzle, 100 and 200 yards, and at the 5 yard increment nearest to maximum point blank range. Quoted MV values are from 24-inch test barrels, to the best of my knowledge. The loads are listed in descending order of their MV.
.338-06, 225 grain Nosler Partition
Muzzle - 2600 fps / 3378 ft.lbs.
100 yards - 2409 fps / 2899 ftlbs.
200 yards - 2226 fps / 2476 ft.lbs.
255 yards - 2129 fps / 2264 ft.lbs.
.35 Whelen, 250 grain Nosler Partition
Muzzle - 2550 fps / 3610 ft.lbs.
100 yards - 2358 fps / 3086 ftlbs.
200 yards - 2174 fps / 2623 ft.lbs.
250 yards - 2085 fps / 2413 ft.lbs.
9.3x62: 286 grain Hornady IL-RP
Muzzle - 2360 fps / 3538 ft.lbs.
100 yards - 2155 fps / 2950 ftlbs.
200 yards - 1961 fps / 2442 ft.lbs.
230 yards - 1905 fps / 2304 ft.lbs.
That MV of these loads decreases with increased bullet diameters and weights is inevitable, given that the three cases have nearly identical powder capacities and similar MAP limits. All three loads generate considerable energy, which is a key variable in computing killing power (below). It is worth noting that the 9.3x62 load, especially, follows the big bore - heavy bullet - moderate velocity formula that has proven so effective on large, tough, and sometimes dangerous game worldwide, and particularly in Africa.
Sectional density (SD) is the ratio of a bullet's weight in pounds to the square of its diameter in inches. SD affects penetration, as all other factors being equal (bullet construction, for example) the bullet with the highest sectional density will penetrate deepest. Obviously, to kill cleanly, any hunting bullet must penetrate into the animal's vitals, so hunting bullet SD is important. For Class 3 game, a SD of .26 has long been considered about the minimum acceptable for rifle cartridges. Here are the SD numbers for our comparison bullets, in descending order.
286 grain (.366"): SD .305
225 grain (.338"): SD .281
250 grain (.358"): SD .279
The SDs of the 225 grain .338” and 250 grain .358” bullets actually exceed that of 270 grain
.375” bullets (SD .274), while the .305 SD of the 286 grain .366” bullet is the same as that of 300 grain .375” bullets. The performance of 270 and 300 grain bullets in the .375 H&H Magnum made that cartridge a legend wherever Class 3 and Class 4 game is hunted. That bullets in
.338, .358, and .366 caliber have comparable SDs says much about their ability to penetrate deep into large, thick-skinned animals.
Killing power is the most difficult factor to estimate, as there is no definitive scientific formula to apply. Various systems have been created to estimate the killing power of rifle cartridges, with varying results in terms of accuracy. Unfortunately, many such systems have no correlation with reality at all.
One of the best, in terms of correlation with reality, has proven to be the G&S Online Rifle Cartridge Killing Power Formula. Not only is it generally consistent with results in the field, it can be used to compare any load at any range and includes the factors of energy at impact (which includes velocity), SD and cross-sectional area in an easy to use formula to arrive at a Killing Power Score (KPS) for a given load at a given distance, via the formula:
KPS at "y" yards = (impact energy at y yards) x (sectional density) x (cross-section area), or simply: KPS @ y = E @ y x SD x A
(Cross-section areas are .0897 sq. in., .1007 sq. in., and .1052 sq. in. for .338 inch, .358 inch, and .366 inch diameter bullets, respectively.)
I calculated the killing power of these loads at 100 and 200 yards, and at the five yard increment closest to each load MPBR, plus KPS values at any additional key distance (noted in italics). Loads are listed in descending order of 100 yard KPS values.
9.3x62, 286 grain load: KPS at 100 yds. = 94.7; KPS at 200 yds. = 78.4; KPS at 230 yds. = 67.7; KPS = 88 at 135 yards
.35 Whelen, 250 grain load: KPS at 100 yds. = 86.6; KPS at 200 yds. = 73.6; KPS at 250 yds. = 67.7; KPS = 68.5 at 240 yards
.338-06, 225 grain load: KPS at 100 yds. = 73.2; KPS at 200 yds. = 62.5; KPS at 255 yds. = 57.2; KPS = 68.5 at 140 yards
These KPS values only have meaning when compared with relevant benchmarks. For these loads, those benchmarks are:
KPS 35 or greater: All Class 3 game (weighing 300+ pounds), but especially those between about 1000 and 1500 pounds (e.g., very large moose, eland)
KPS 68.5 or greater: Dangerous thin-skinned Class 4 game (e.g., leopard, lion, grizzly bear)
KPS 88 or greater: Large thick-skinned dangerous game (e.g., Cape buffalo, rhino, elephant)
(See The G&S Online Killing Power Formula: Take 2 https://www.chuckhawks.com/killing_power_formula-2.html if you are unfamiliar with the G&S Online Killing Power Formula or the interpretation of KPS values as they relate to different sizes/types of game animals.)
All three loads have KPS values well above 35 at their MPBR distances; thus these loads have killing power to spare for any Class 3 game animal. Further, the loads have the power to reliably take Class 4 game, with some qualifications and restrictions.
We have set a KPS value of 68.5 as the baseline for using a cartridge and load on “thin-skinned Class 4 game,” meaning smaller game animals that are considered extremely dangerous (such as the big cats and great bears). By this KPS baseline, the 9.3x62 load has adequate killing power on these animals out to its 230 yard MPBR (67.7 is close enough to 68.5 for me); the .35 Whelen and .338-06 loads get equivalent killing power out to 240 and 140 yards, respectively.
Finally, a KPS of 88 is our baseline for load power against the big, tough, and mean stuff, such as the big wild cattle (Cape and water buffalo), rhino, and elephant. The 9.3x62 load has this unrestricted Class 4 capability out to 135 yards, while the .35 Whelen load could be so used at under 100 yards. The 225 grain .338-06 load does not get this level of power at any range, though a 250 grain load would do so at short distances.
Our KPS parameters and results assume vital area hits, of course. A game animal hit somewhere other than in the vitals is not likely to go down cleanly, no matter the size, weight and impact energy of the bullet. This is why I preach the, "never take a shot beyond MPBR, and closer is always better" doctrine. Shorter range shots improve the likelihood of placing a bullet in the right place.
Rifles chambered in these cartridges generate significant kick. Estimated recoil energy in a 9 pound rifle is 27.6 ft.lbs. for the 225 grain .338-06 load, 30.6 ft.lbs. for the 250 grain .35 Whelen load, and 32.0 ft.lbs. for the 286 grain 9.3x62 load.
By comparison, 270 and 300 grain .375 H&H Mag. loads generate about 38.5 and 42 ft.lbs. of recoil (in a 10 pound rifle); estimated recoil of a typical 250 grain .338 Winchester Mag. load in a 9 pound rifle is 36.7 ft.lbs. Recoil of our subject cartridges and loads ranges from 13 percent to 25 percent less than the .338 Win. Mag. load just cited. As another comparison, the .35 Whelen load has the same estimated recoil as a 200 grain .300 Win. Mag. load.
Recoil tolerance is an individual thing, so each shooter has to make his/her own judgments regarding whether one or another rifle/cartridge/load package kicks too much. For me, the recoil of these cartridges would be manageable, but not comfortable.
Acquiring a rifle and ammo
I mentioned earlier that new production rifles in these calibers are virtually unobtainable, and that factory ammunition choices are severely limited (and generally quite expensive). Thus anyone who sets their heart on owning and shooting a rifle chambered for any of these cartridges will need to consider their options.
Concerning rifles, the obvious options include (1) finding a suitable rifle on the secondary market, (2) having a .30-06 rechambered and the barrel rebored, (2a) having a new barrel, chambered in the desired caliber, installed on a .30-06 action, (3) having a semi-custom or custom rifle built in the desired caliber.
There are so many variables involved in pursuing options (1), (2), and (2a) that I will not comment on them further. I do have a couple of examples/suggestions regarding option (3), and can even ballpark the cost of acquiring a rifle in this manner.
My go-to example of the build options and cost of acquiring a semi-custom rifle is Shaw Custom Rifles. Shaw will cheerfully build you one of their Mk. VII or Mk. X (an enhanced Mk. VII) rifles in any of these calibers. Base price of a Mk. VII build is about $1,000 and can go up to as much as $1,600, depending on options you select. The Mk. X rifle base price is about $1,400, and again options can add some hundreds of dollars to that. Details and an online build-your-rifle program are on the Shaw website, www.shawcustombarrels.com.
Jarrett Rifles is one example of what one can get in a true custom rifle build. The Jarrett Legendary Beanfield Rifle, for instance, has a base price just over $6,000, and there are several other more expensive rifle models available. Go to https://www.jarrettrifles.com/rifle-models.html and be prepared to drool.
Did I mention that factory ammo options for these cartridges are limited and that the stuff may be expensive? As of August, 2019, MidwayUSA lists only 5 loads for the .338-06, all priced at $80 per 20 round box; there are 10 .35 Whelen loads listed, ranging in price from $30 to $60 per box; there are also 10 9.3x62 loads listed, priced from $30 to $100 per box.
The point is that anyone who shoots one of these calibers could gain a lot by reloading. First, a reloader has many options in bullets (weights and specific brands and types) not available in the sketchy selection of factory ammo. Second, reloading can substantially reduce the cost of shooting these cartridges.
Just for fun, I did a quick variable cost analysis of reloaded ammo for the .338-06. Depending on the the bullet used, I came up with a reload cost of 85 cents to $1.00 per round, compared to a cost of $4.00 per round ($80 per box) for the one brand of available .338-06 factory ammo.
A critical assumption contributing to the low variable cost in this example concerns the brass used. Virgin brass for these cartridges is only sporadically available and is quite expensive. (I found two sources of Norma .338-06 brass, priced at about $1.50 per piece) However, a reloader can resize .30-06 brass to any of these calibers without undue sweat or headaches.
.30-06 brass is abundant and inexpensive (about 50 cents per piece). I assumed that I could expect to get a total of four loadings and firings out of each piece of sized-up .30-06 brass, which means that the per-load average cost of brass would be only about 13 cents.
This is not the time or place to go into detail regarding the techniques of resizing rifle brass. One can get guidance from any comprehensive reloading guide, if needed. The only thing I would suggest is that I would use a 2-step process if I were resizing .30-06 brass to .35 Whelen or 9.3x62; i.e., I would get a .338-06 sizing die and first size-up my brass with that, then I would size it on up with the .35 Whelen or 9.3x62 die. Extra work, I know, but I believe one would get better resized brass this way.
Realistically, very few hunters need a powerful medium bore rifle, whatever the specific caliber. For those who have opportunity to hunt trophy elk, moose, or the great bears in North America, or the larger African plains game or cats, a powerful medium bore would be highly desirable (and might be mandated by game laws in some jurisdictions).
In my opinion, a .338-06, stoked with suitable loads, is enough gun for anything one can hunt in North America. If a safari for African plains game is on the bucket list, a 9.3x62 rifle would be in play as a suitable tool. Or one could split the difference and use a .35 Whelen for both situations. (I know, a .338 Win. Mag. can do all that and perhaps more, but we are exploring alternatives here.)
The bottom line is that the .338-06, .35 Whelen, and 9.3x62 are truly under-appreciated, regarding their power and utility. For anyone who needs or wants a highly capable medium bore rifle, one of these might suit better than the very few more common and popular cartridges.
Copyright 2020 by Gary Zinn and/or chuckhawks.com. All rights reserved.