Compared: The .338 Marlin Express and .338 Federal
By Chuck Hawks
The .338 Federal and .338 Marlin Express are recently introduced rifle cartridges that attempt to bring medium bore performance to short action hunting rifles, without magnum level recoil. Both cartridges succeed to a considerable extent, although they are loaded to maximize performance from their relatively small cases, rather than to minimize recoil. Never the less, it cannot be denied that they kick less than the .338 Win. Mag., the top sellling medium bore rifle cartridge, in guns of similar weight.
.338 Marlin Express
Toward the end of 2008, Hornady and Marlin formally introduced a new rimmed cartridge for the Model 336XLR lever action rifle named the .338 Marlin Express. I am rather proud of the fact that I suggested, in writing, a .338 cartridge for use in the Marlin 336 lever action to the powers that be at Hornady and Marlin right around the time the .338 Marlin Express was being designed and about two years before it was introduced.
This cartridge is based on a unique case and uses a new 200 grain Hornady Flex-Tip spitzer bullet and the latest non-canister powders to achieve a MV of 2565 fps. The .338 Marlin is big news for traditional lever action rifle fans.
The .338 and .308 Marlin Express cartridges have convincingly demonstrated what can be accomplished by using the latest propellants in relatively small cases. The .338 Marlin case looks something like a rimmed .338 Federal, but it is both fatter and shorter. Its performance on large game has proven to be excellent.
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 rather than the 7x57 Mauser case. (Remember, when Jack O'Connor proposed the .338x57 there was no .308 case, as the .308 Winchester had not yet been invented.) Apparently great minds travel similar paths!
Unlike the .338x57 O'Connor, the .338 Federal is loaded to maximum pressure with the latest (non-canister) powders to achieve the highest possible level of performance from its short action case. The .338 Federal 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. It is not intended for use in rifles with tubular magazines, such as the Marlin 336, Winchester 94 and Henry lever actions.
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, 185 grain Barnes TSX bullet at a MV of 2750 fps and 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.
The comparison loads
The initial Hornady factory load for the .338 Marlin Express drives a 200 grain FTX boat-tail spitzer bullet (BC .430) at a MV of 2565 fps. That will be our comparison load for the .338 Marlin. Remington is scheduled to add the .308 and .338 Marlins to their extensive loading list in 2010, but their .338 Marlin load is not yet available as I write this article.
My favorite factory load for the .338 Federal is the 210 Nosler Partition (NP) spitzer at a MV of 2630 fps. This is the load that I will use to represent the .338 Federal. Both the .338 Federal and .338 Marlin Express use standard .338" diameter bullets, which are widely available to reloaders.
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. Here are the SD numbers for our chosen bullets.
The slightly heavier bullet chosen to represent the .338 Federal gives it a modest advantage in SD and thus, other things being equal, penetration. For comparison, the SD of a 165 grain .308 bullet is .248.
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 cross wind. 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. Here are the BC numbers of our various bullets.
Although both bullets are spitzers (pointed), the sleek Hornady FTX bullet gives the .338 Marlin Express a modest advantage in BC. We will soon see how this influences downrange trajectory.
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 and similar data is provided in the bullet maker's reloading handbooks. This makes comparing calibers and loads far more convenient than it might otherwise be. 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, a common generalization, both of our cartridges should be adequate for shooting elk to beyond 300 yards. The .338 Federal is loaded to higher pressure (about 63,000 psi) than the .338 Marlin Express (around 47,000 psi) and that is reflected here.
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 (MPBR) +/- 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 any 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.
As the figures above show, the .338 Marlin and .338 Federal are very similar in MPBR. The .338 Marlin's FTX bullet's superior BC helped close the gap on the higher velocity .338 Federal and its Nosler Partition bullet. These short action .338's shoot considerably flatter than traditional woods cartridges, whose MPBR with typical factory loads is usually not more than 200 yards.
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 of Guns and Shooting Online.) Here are the Optimum Game Weight results for our loads at the muzzle, 100, 200 and 300 yards.
One needs to be careful when drawing conclusions from killing power estimates, but we can see that the .338 Federal's superior velocity and energy give it an advantage in OGW. That, of course, is as it should be, since we are comparing two cartridges of the same caliber.
Considering that the average male Rocky Mountain elk is estimated to weigh about 500 pounds, both of our .338's are satisfactory elk cartridges at or beyond their MPBR. Very few hunters need more rifle than this. These cartridges could also serve as "all around" African hunting calibers, suitable for all 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.
The .338 Marlin Express comes within 0.1 ft. lb. of the 20 ft. lb. recoil energy limit, although the .338 Federal can be loaded down to that level using a 200 grain bullet at a MV of approximately 2450 fps. At 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.
The .338 Marlin Express is the latest medium bore cartridge intended for use in lever action rifles. It follows in the footsteps of the .33 Winchester, .348 Winchester and .356 Winchester. Teamed with the Marlin XLR rifle, it may well be the finest woods and big game rifle/cartridge combination made today.
The .338 Federal is perhaps the most promising medium bore cartridge to have been introduced in decades. Being a rimless design, it can easily be adapted to autoloading and bolt action rifles. I am a fan of the cartridge, but I fear that excessive recoil will limit its popularity, just as it did the .338-06, .358 Win. and .35 Whelen before it. Sales of .338 Federal rifles already seems to have stalled and I believe that recoil is the reason. ATK/Federal Cartridge really needs to introduce, and promote for general use, a Low Recoil load for their .338 that duplicates the ballistics of the .338x57 O'Connor.
That concludes the comparison of these two outstanding .338 caliber cartridges. They deserve more support and popularity than they have so far received. I sincerely hope that the .338 Federal and the .338 Marlin Express will catch on with mainstream shooters.
Copyright 2007, 2012 by Chuck Hawks. All rights reserved.