Compared: .308 Marlin Express and .307 Winchester
By Chuck Hawks
This is an interesting comparison, as the .308 Marlin Express was designed for the same mission as the previous .307 Winchester, namely to create a modern all-around cartridge for traditional lever action rifles (the Marlin Model 336 and Winchester Model 94). The .307 was Winchester's 1982 attempt and the .308 Marlin is Marlin's 2007 attempt to meet this goal. Both are similar to and follow in the footsteps of the .300 Savage, introduced in 1920.
The .307 Winchester
The .307 Winchester case is essentially a thick walled, rimmed, version of the .308 Winchester case. .308 Winchester reloading dies can even be use for reloading .307 Winchester cartridges, although the proper shell holder is the one designed for the rimmed .30-30 case.
This very strong case, along with a beefed-up version of the famous Winchester Model 94 rifle called the Big Bore, allowed the .307 cartridge to be standardized at a SAAMI maximum average pressure (MAP) of 52,000 cup, the same as the parent .308 Win. This is a markedly higher pressure limit than the earlier .300 Savage (46,000 cup) or the later .308 Marlin, which is about equal to the .300 Savage in MAP. As far as I know, the .307 and its sister cartridge the .356 Winchester (the same case necked-up to accept .358" bullets) are the highest pressure cartridges ever designed for the Model 94 rifle. Soon after the introduction of the .307 Winchester, Marlin responded by chambering their Model 336 rifle for the cartridge.
Unfortunately, the .307 was something of a sales flop in both the Marlin and Winchester rifles. My theory is that there are three main reasons for this. One, the .307 was forced to use the same flat nosed bullets as the .30-30 due to the tubular magazines of traditional Winchester and Marlin lever guns, so it shed its extra velocity fast. Two, the .307 was mostly chambered in carbines with 20" barrels that robbed much of its improved performance. And three, the .307 kicked noticeably harder than the established .30-30 with which it primarily competed. Neither the Marlin 336 nor Winchester 94 rifles of 1982 had stocks designed to ameliorate the recoil of a high intensity cartridge like the .307. They both had hard, relatively small butt plates and too much drop at the comb, particularly when used with the telescopic sights needed to take advantage of the ballistic performance of the .307 cartridge.
Winchester, alone of the major ammunition manufacturers, still offers factory loaded ammo in .307, as do smaller specialty companies such as Stars and Stripes (www.starsandstripes.com). The sole remaining Winchester .307 factory load drives a 180 grain Power Point bullet at a MV of 2510 fps from a 24" test barrel, and that is the load that we will use for this comparison.
The .308 Marlin Express
The .308 Marlin allegedly grew out of experiments by Hornady technicians with their 160 grain Evolution .30-30 bullet in the .307 Winchester cartridge. The eventual result of these experiments was a partnership with Marlin Firearms and a new, unique rimmed case that became the .308 Marlin Express. This new case resembles a .307 Winchester case with its shoulder set back .0998".
The new case was specifically designed for a new version of the 160 grain Evolution bullet with a longer ogive and a higher ballistic coefficient than the previous Evolution bullet designed for the .30-30 cartridge. The new cartridge uses non-canister powders designed to give a complete burn in the 24" barrel of the Marlin Model 336XLR rifle. The .308 Marlin has a maximum cartridge overall length of 2.60" and is loaded with the new .308" diameter, 160 grain Hornady Evolution bullet. The MAP of the new cartridge has not been standardized by SAAMI as of this time, but it is expected to be about 46,000 cup.
The justification for the existence of the .308 Marlin Express is Hornady's new soft-tipped, boat-tail Evolution spitzer bullet. This bullet incorporates a semi-soft plastic tip that makes it safe to load in tubular magazines and brings spitzer bullet performance to traditional lever action rifles.
The Marlin 336XLR is the only rifle now available in .308 Marlin, but the cartridge is brand new at this writing and that situation may change. The 336XLR addresses the shortcomings of the earlier Model 336 carbine that was offered in .307 Win. The XLR has a stainless steel barreled action, is heavier, comes with a 24" barrel to take full ballistic advantage of the new cartridge, uses a half magazine without a barrel band to improve accuracy, and its laminated stock is fitted with a modern recoil pad. The XLR is a serious hunting rifle.
Hornady figures show that their .308 Marlin LEVERevolution (LE) load gives the 160 grain Evolution bullet a muzzle velocity (MV) of 2660 fps from a 24" barrel. Since that is the only load available for the .308 Marlin as I write these words, that is the load that we will use in this comparison.
We will compare the .307 Win. and .308 Marlin in sectional density (SD), velocity, energy, trajectory, killing power, and recoil. The .308 Marlin and .307 Winchester shoot standard .308" bullets. All .308" bullets have a frontal area of .0745 square inch, regardless of style or weight, so bullet cross-sectional area is not a consideration in this comparison.
Sectional density is defined as a bullet's weight (in pounds) divided by the square of its diameter (in inches). The sectional density of the bullet, other factors being equal, greatly influences its penetration. The greater the SD the greater the potential for penetration. (For more on the subject of sectional density, see my article "The Sectional Density of Rifle Bullets" on the Rifle Information Page.)
It is a combination of wound channel diameter and length that determine the total amount of tissue damaged by a bullet, and consequently how well it kills. Obviously, a bullet must penetrate into an animal's vitals to insure a quick and humane kill. Here are the SD numbers for the bullets we are comparing:
In terms of SD, the .307 Winchester clearly has the advantage. A SD of .220 would be considered entirely satisfactory for shooting deer, and a SD of .270 or better is very good for large game like elk and moose. The 160 grain .308 Marlin bullet lies between these bench marks and can be viewed as a reasonable all-around bullet choice.
Bullet velocity is the most important component of energy and also flattens trajectory. Here are the velocities from the muzzle (MV) to 300 yards in feet per second for our selected loads.
The .308 Marlin has the initial velocity advantage due to its lighter bullet, and that advantage increases down range due to the much lower air drag of its boat-tail spitzer bullet compared to the flat-nose, flat base .307 bullet.
Bullet energy is easy to compute and widely compared. It is a function of a bullet's weight and the square of its velocity. Kinetic energy, measured in foot pounds (ft. lbs.), is an important factor in a cartridge's potential killing power. Energy is a way to measure the ability to do "work," which in this case means to power the bullet expansion and penetration necessary to humanely kill game. Here are the energy figures in foot pounds for our selected loads from the muzzle (ME) to 300 yards.
The two loads start out virtually equal in energy, but the comparatively rapid velocity loss occasioned by the .307's blunt bullet means that it sheds its initial energy rapidly. The advantages conferred on the .308 by its high tech bullet are becoming clear.
Trajectory is important to shooters and hunters because the flatter the bullet's trajectory the easier it is to achieve precise bullet placement at long and unknown ranges. And bullet placement is, by far, the most important factor in killing power. The primary factors influencing trajectory are bullet velocity and ballistic coefficient, a measure of the bullet's air drag.
The following trajectories, shown in inches above or below the line of sight, are computed for the maximum point blank range (MPBR) +/- 3" of each load and assume an optical sight mounted 1.5" over bore.
The MPBR of the .308 Marlin is 261 yards, and the MPBR of the .307 Winchester is 231 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. As you can see, the .308 shoots flatter than the .307 due to its higher velocity and sleeker bullet.
There are lots of formulas and methods for estimating killing power. The best system that I have encountered for estimating the killing power of specific big game hunting rifle loads, and the only one I know of that attempts to relate killing power to the weight of game animals and the distance at which they are shot, was developed by Edward A. Matunas and published in the Lyman 47th Reloading Handbook. It is not perfect, but it gets you in the ballpark and correlates well with reality. He calls it the "Optimum Game Weight Formula," and I thought enough of it to apply it to a great number of cartridges and loads, which you can see in the "Optimal Game Weight Table" on the Tables, Charts and Lists Page. Here are the Optimum Game Weight results for our loads at 100, 200, and 300 yards.
Once again the higher velocity and BC of the .308 Marlin's Evolution bullet dominates the comparison. If an elk weighs about 500 pounds, the .307 is a 100 yard elk caliber and the .308 Marlin is about a 150 yard elk caliber. For killing deer, both are limited by their MPBR rather than their killing power as measured by the OGW method.
Recoil is unavoidable, but bad. It disrupts the shooter's concentration and makes accurate bullet placement more difficult. And the more recoil there is, the worse its effect on the shooter. Here are the approximate recoil energy (in foot pounds) and recoil velocity (in feet per second) figures for our loads when fired in 8 pound rifles.
These figures reveal that the .308 Marlin kicks noticeably less than the .307 Winchester. This is due primarily to the .307's 20 grain heavier bullet. It is actually above the 15 ft. lb. recoil energy limit that most shooters find reasonably endurable.
These two cartridge are based on cases of similar capacity, and the .307 Winchester is loaded to substantially higher pressure, which should give it superior performance. But it is betrayed by its heavy, flat point bullet. Hornady's development of the Flex-Tip Evolution bullet more than negates the .307's potential advantages. It is this more aerodynamic bullet that makes all the difference in downrange performance between the two cartridges and leaves the .308 Marlin Express the clear winner of this comparison.
Copyright 2006, 2012 by Chuck Hawks. All rights reserved.