Compared: .338 Federal and .338-06 A-Square
By Chuck Hawks
About two years after Guns and Shooting Online started promoting the .338x57 O'Connor, Federal announced the .338 Federal, a similar cartridge but based on the .308 Winchester case (instead of the 7x57 Mauser case) necked-up to accept .338" bullets. The .338 Federal is loaded to maximum pressure (about 63,000 psi) with non-canister powders to achieve the highest possible level of performance from its short action case. It is a rimless cartridge and uses spitzer bullets, so it is best adapted to modern single shot rifles and repeating rifles fed from box or spool type magazines.
ATK/Federal Cartridge offers three .338 loads in their Federal Premium line and one in the Fusion line. The Premium offerings include a 180 grain Nosler AccuBond bullet at a MV of 2830 fps, a 185 grain Barnes TSX bullet at a MV of 2750 fps and a 210 grain Nosler Partition at a MV of 2630 fps. The Fusion load drives a 200 grain spitzer bullet at a MV of 2725 fps. Just as the .308 Winchester was designed to achieve near .30-06 performance from a short action case, the .338 Federal is designed to achieve near .338-06 performance from a short action case.
The .338-06 A-Square started life as a wildcat based on the full length .30-06 case simply necked-up to accept .338" bullets. Premium ammo and rifle maker A-Square ushered the cartridge through the SAAMI standardization process and legitimized it in 1998, adding it to their ammunition line. Weatherby subsequently added the .338-06 to their ammunition line and A-Square and Weatherby both offer rifles in the caliber.
The .338-06 is a powerful cartridge, using bullets of the same weight as the .35 Whelen (.35-06), but with superior sectional density and at higher pressure for increased velocity. 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 Weatherby factory load uses a 210 Nosler Partition bullet at a MV of 2750 fps.
The purpose of this comparison is to see how these two cartridges relate to each other. So, to be fair, what loads shall we compare?
In .338 Federal my factory load of choice is the 210 Nosler Partition (NP) spitzer at a MV of 2630 fps, so that is the load that will represent the .338 Federal. Coincidentally, the Weatherby factory load for the .338-06 A-Square uses that same bullet, but at a MV of 2750 fps, so that will be our representative .338-06 load. The difference in velocity is due to the difference in case capacity; short cases hold less propellant than longer cases of the same diameter and these are both rimless cases with a .473" rim/head diameter.
Bullet cross-sectional area
Both of these cartridges use .338" diameter bullets and therefore have an identical cross-sectional area of 0.0891 square inch. Bullet cross-sectional area, of course, affects the diameter of the wound channel a bullet creates as it punches through an animal and a .338 bullet creates a substantially wider path of destruction than a .30 caliber or 8mm bullet.
Sectional Density and Ballistic Coefficient
Sectional density (SD) is the ratio of a bullet's weight to the square of its diameter. The higher the SD number, the greater its length in proportion to its mass. SD is relevant because, other things being equal, a heavier bullet of a given diameter penetrates deeper than a lighter bullet of the same diameter. The more penetration a bullet achieves, the longer the wound channel it creates, until it exits the far side of the animal. SD numbers from .250 up are generally considered adequate for CXP3 game with .338 cartridges. The 210 grain Nosler Partition bullet loaded in these two cartridges has a .263 SD.
Ballistic coefficient is calculated as the ratio of a bullet's SD to its coefficient of form. It is used to judge a bullet's drag as it flies through the atmosphere. The higher the BC, the lower the drag and the less the bullet is affected by air resistance and also crosswind. In other words, the higher the BC the more streamlined the bullet. BC has an important effect on the downrange trajectory of rifle bullets. At any given muzzle velocity, the bullet with a higher BC will shoot flatter. The BC of the 210 grain Nosler Partition bullet is .400.
Velocity and energy
Velocity matters because it flattens trajectory and is the major component of kinetic energy. Energy powers bullet expansion and penetration, without which there would be no killing power.
Velocity and energy figures at various ranges are published by the ammo makers for their factory loaded ammunition. Here are the velocity (in feet per second) and kinetic energy (in foot pounds) figures for our selected loads at the muzzle, 100, 200 and 300 yards.
If around 1200 ft. lbs. of kinetic energy at bullet impact are required to humanely harvest elk, as is sometimes claimed, our cartridges are in pretty good shape to beyond 300 yards, which is beyond their maximum point blank range (MPBR).
The distance at which a bullet drops 3" below the line of sight, when zeroed so that its maximum rise above the line of sight is limited to 3", is that load's maximum point blank range +/- 3". Thus, a given load's maximum allowable deviation above or below the line of sight from the muzzle to its MPBR is only 3". This means that you can hold on the center of the heart/lung area of any big game animal from the muzzle out to the cartridge's MPBR without fear of shooting over or necessity to adjust for bullet drop.
When so sighted and fired from a rifle with a scope mounted 1.5" over bore, the maximum point blank range (+/- 3") of our comparison loads would be as follows.
The .338 Federal is within 11 yards of the .338-06 in MPBR, which is not bad considering its substantially lower MV and (as we shall see) lower recoil.
OGW killing power
Killing power is very hard 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. To make a complicated issue worse, most killing power formulas are devised to validate the author's point of view on the matter and have no valid correlation with broad spectrum results in the field.
In my opinion, one of the most useful 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. Most of all, OGW seems to have a positive correlation with actual results in the field. (There is an extensive OGW table on the Tables, Charts and Lists page.) Here are the Optimum Game Weight results for our various loads at the muzzle, 100, 200 and 300 yards.
One should be careful when drawing conclusions from killing power estimates, but we can see that as velocity and energy increase, so does the estimated killing power. That, of course, is as it should be, since we are comparing cartridges of a single caliber. Considering that the average bull elk is estimated to weigh about 500 pounds, the .338 Federal and .338-06 A-Square have optimum power to kill elk beyond the MPBR of either cartridge. In practical terms, very few hunters need more cartridge than this. These calibers can also serve as African medium bores, suitable for all large plains game except the dangerous CXP4 critters.
Here are the recoil energy (in foot pounds) and recoil velocity (in feet per second) figures for our comparison loads when fired in 8 pound rifles.
At about 22 ft. lbs. in an 8 pound rifle (and an unseemly 25 ft. lbs. in a 7 pound Kimber 84M Classic), the .338 Federal has plenty of power at both ends. Ditto the .338 A-Square, which kicks noticeably harder than the .338 Federal. Neither of these are appropriate cartridges for recoil sensitive shooters, unless they are fed reduced power handloads. For that purpose, the .338 Federal is the better choice, due to its smaller case capacity.
The .338 Federal is perhaps the most promising medium bore, rimless cartridge to have been introduced in decades. I am a fan of the .338 Federal, but I fear that excessive recoil will ultimately limit its popularity, just as it has the .338-06, .348 Win., .358 Win. and .35 Whelen. ATK/Federal Cartridge really needs to introduce, and promote for general use, a Low Recoil load for their .338 that drives a 200 grain bullet at a MV around 2450 fps. Savvy reloaders, of course, are already doing this.
I read a review of the Kimber 84M/.338 Federal in Rifle Shooter magazine in which the author glossed over the recoil issue by describing it this way: ". . . surprisingly light recoil given the rifle's minimal heft." Translation: since all lightweight rifles chambered for powerful cartridges kick like the devil, the author (an experienced shooter) wasn't surprised! Such subterfuge may sell a few rifles and cartridges, but as it does the word is going to get around the shooting ranges and hunting camps that .338 Federal rifles are unpleasant to shoot. That has already happened to the .338 A-Square.
The .338-06 A-Square is an fine medium bore cartridge, versatile and powerful. It can easily handle bullets weighing up to 250 grains (SD .313), which cannot be said of the .338 Federal. It can do more than any other standard medium bore cartridge up to the 9.3x62mm and it is an excellent African plains game cartridge. (There is a comparison article featuring the .338-06, .35 Whelen and 9.3x62 on the Rifle Cartridges page.)
Unfortunately, since its 1998 introduction as a commercial cartridge, the .338-06 has failed to set the shooting world on fire. I am convinced that there are at least three reasons for this: 1) there are no popular priced .338-06 factory loads on the market and no popular priced rifles; 2) it kicks too hard and most hunters find it unpleasant to shoot; 3) guns and ammunition for the best selling .338 Win. Mag. are less expensive and far more widely available. Consequently, the .338 A-Square is selling poorly in Weatherby Mark V rifles, which is a pity. Weatherby should offer the .338-06 A-Square in their excellent, but less expensive, Vanguard rifles and Hornady, the most innovative of the big U.S. ammo producers, should kick over the traces and offer .338-06 factory loads with 200 and 250 grain bullets.
Copyright 2010, 2012 by Chuck Hawks. All rights reserved.