The release of the .338 Winchester Magnum in 1958 sparked the creation of two more .338 cartridges soon after, the proprietary .340 Weatherby Magnum and the .338-06 wildcat. The .338-06 was based on the .30-06 case necked up to take .338” bullets with no other change. This immediately made the former but similar .333 OKH (see .338 Winchester Magnum) wildcat near obsolete due to the more readily available .338 caliber projectiles. The slight step up in bore diameter was in effect, the final evolution of Elmer Keith’s favored medium bore cartridge design.
The .338-06 steadily grew in popularity, mostly within the US, to a point where during the 1990’s it seemed inevitable that this cartridge would become a mainstream factory chambering. Instead, Winchester and Remington ballistic engineers became focused on the development of magnum powered cartridges based loosely on the 404 Jeffery case. Winchester developed its line of short magnum cartridges which would hopefully eventually include a .338. However; when Winchester engineers began experimenting with a .338 short magnum, it was found that the cartridge did not produce magnum performance but duplicated the .338-06. To this end Winchester released the .325WSM. Remington opted for the high power .338 RUM. Oddly, despite the continued popularity of the .338-06, Federal introduced the .338 Federal, based on the .308Win case necked up to .338.
Although the .338-06 was not adopted by the big brands, this cartridge was nevertheless standardized and was to a limited extent a factory chambering. During the 1980’s the 338-06 was adopted by the U.S semi-custom rifle and ammunition manufacturing company A-Square. Founded by Lieutenant Colonel Arthur B Alphin in 1979, A-Square was one of the few members of the Small Arms and Ammunition Manufacturers Institute (SAAMI) donating time and money towards the rigorous testing of ammunition and chambers. This work results in the standardization of factory cartridges and rifle chambers allowing hunters to buy a rifle of for instance Winchester brand and use Remington ammunition in the rifle safely, a vital service to the industry. A-Square’s adoption of the .338-06 enabled the cartridge and chamber specifications to be SAAMI standardized. Due to this establishment, the standardized cartridge can be referred to as the .338-06 A-Square.
A-Square closed its doors in 2012, a thoroughly well respected company retired with dignity.
The .338-06 A-Square maintains a small level of popularity, enjoyed as a practical larger medium game cartridge, a working cartridge that can be relied on to get the job done. This cartridge is not to be confused with the .338 A-Square, a now rare belted magnum designed by Alphin of A-Square. This cartridge was based on the .378 Weatherby necked down to .338 caliber with a 35 degree shoulder angle rather than the traditional Weatherby radius. Performance was identical to the current .338-378 Weatherby Magnum.
The key consideration of the .338-06 A-Square is game body weights.
While I have discussed .338 projectile performance within the .338 Winchester Magnum text, the differing muzzle velocities between the .338 Win Mag and .338-06 A-Square have a major effect on results with game body weights being a major influence.
Although the medium bores are often expected to produce wider and fasting killing wound channels than smaller bores when used on light through to large game, .338” bullets traveling at velocities below 2600fps can be slow killers with rear lung shots, most specifically if body weight resistance is less than optimal.
On game weighing less than 90kg (200lb) and viewing game broadside, shots that strike in line or slightly forwards of the foreleg produce the fastest kills, often inside 2-3 yards. Shots that’s strike behind the foreleg into the heart or higher and into the rear lungs can allow animals to escape considerable distances. Bullet design and bullet weight also influence results. As an example, 180 to 200 grain fast expanding bullets can be driven fast enough to deliver hydrostatic shock on light through to mid weight game at close to moderate ranges. The frangible Rocky Mountain 225 grain ULD can anchor lean game very quickly with rear lung shots, down to very low velocities.
As body weights are increased, the .338-06 comes into its own. Those who live or hunt in areas where game typically weigh between 90 and 320kg (200-700lb) while occasionally taking heavier game, will find the .338-06 A-Square to be a noble cartridge. Low impact velocities will still allow rear lung shot game to run- however a good measure of target resistance ensures maximum energy transfer with a wide range of bullet designs.
On large animals in the 450kg (1000lb) range and heavier, the .338-06 A-Square again does not produce enough velocity to initiate hydrostatic shock. By the same token, it cannot produce wide wounding in the same manner as the magnums, especially those of a wider bore diameter. Nevertheless, with both careful bullet selection and shot placement, the .338-06 A-Square can be relied on in a utilitarian manner. Heavy bullets of suitable construction driven at low velocities can be used to break through large shoulder bones and penetrate through to and destroy vitals. That said, on densely muscled game such as bovines, a good deal of energy and wounding potential can be lost when heavy bone is encountered. Nevertheless, the .338-06 A-Square can be used in such roles. In order to produce faster kills on heavy game with both front and rear lung shots, wider bores are more effective. Long for caliber bullets of .338” diameter must be driven fast to obtain similar performance.
The .338-06 A-Square places less stress on projectiles than the magnums. This can be both good and bad. Generally speaking, .338 caliber bullets are made slightly tougher than their small bore counterparts. The negative result of this can be a lack of energy transfer on lean game. In contrast to this, the mild velocities of the .338-06 A-Square can allow the shooter to tackle a wide range of game body weights without being reliant on premium bullet designs with the exception of heavy game. This factor adds further weight to the .338-06 A-Square being a reliable utilitarian cartridge for those who mostly hunt large bodied medium game.
As already suggested, shot placement has a major effect on the performance of this cartridge. Those who primarily utilize meat saver shots may find the .338-06 A-Square to be far from spectacular while those who take shoulder shots will find this cartridge to be emphatic and less reliant on matching bullets to game body weights with regard to light or lean game. Obviously, precise shot placement can be a tricky affair in the field, especially at extended ranges. Here again we find varied results, the skilled shooter with an accurate rifle achieving consistently fast kills, the novice having less than ideal results. By the same token, the woods hunter who is able to utilize high impact velocities will see very emphatic kills while those who shoot at extended ranges and pay less attention to bullet design and shot placement will see different results.
As for the effective range of the .338-06 A-Square, this again comes down to bullet designs and field accuracy. This cartridge is an emphatic bush / woods hunting cartridge on lean through to large bodied medium game and adequate for relatively heavy game. But as ranges are extended, component selection can become somewhat more critical. Many premium projectiles do their best work at impact velocities of 2400fps and above- basically very close woods ranges for the .338-06. A vast majority of projectiles lose the ability to create broad wounding below 2200fps or a range of around 150 to 200 yards but can produce wide wounding down to 1800fps or roughly 400 yards with carefully placed shoulder shots- again shot placement becomes a key issue. The Rocky Mountain ULD can be put to use out to ranges of 1000 yards and beyond in expert hands and is adequate for use on game up to the size of Elk. Again, effective range is relative to both bullet design and field accuracy.
