Compared: Closely Related 7mm and .30 Caliber Cartridges (7mm-08 Remington and .308 Winchester, .280 Remington and .30-06 Springfield, 7mm Remington Mag. and .300 Winchester Mag.)
By Gary Zinn
It is no secret that the 7mm-08 Remington and .280 Remington cartridges are descendants of the .308 Winchester and .30-06, respectively. The 7mm Remington Magnum and .300 Winchester Magnum are based on necked-down .458 Win. Mag. cases with a 25 degree shoulder. These 7mm (.284" diameter) and .308 caliber pairs have performance characteristics that are similar in many ways, but there are also some important differences.
I thought it would be interesting to examine the relative ballistic performance of each pair of cartridges, to illustrate the similarities and differences between them. For brevity, this examination is based on one commercial load for each cartridge; thus it is indicative, rather than comprehensive. (A link to detailed articles on each cartridge is provided at the end of this article.)
However, the particular load I use for each cartridge is not an arbitrary choice. Rather, I selected loads for each caliber pairing that feature bullets with equal, or nearly equal, sectional densities (SD). High intensity 7mm and .308 cartridges are most suitable for hunting Class 2 or Class 3 game animals, depending on the terminal power of particular loads at any relevant range. The loads with matched SD values in each cartridge pairing were chosen with this consideration in mind. (See The Sectional Density of Rifle Bullets for a fuller discussion of sectional density and SD values suitable for different classes of game.)
Here are the bullet weights and SD values of loads that I chose for the analysis:
7mm-08 Rem. (140 grain, SD .248) vs. .308 Win. (165 grain, SD .248)
.280 Rem. (150 grain, SD .266) vs. .30-06 (178 grain, SD .268)
7mm Rem. Mag. (162 grain, SD .287) vs. .300 Win. Mag. (190 grain, SD .286)
The listing for each load includes the brand, bullet weight and type, stated muzzle velocity (from a 24" barrel) and the ballistic coefficient and sectional density of the bullet. The +/-3" maximum point blank range (MPBR) and far zero are noted. Finally, the estimated recoil energy of each load is noted, in an 8.5 pound field weight rifle.
Then, the bullet's energy is listed at 100 and 200 yards, plus at the MPBR distance (to the nearest five yard increment). Next, the Guns and Shooting Online Killing Power Score (KPS) of the load is noted, at each of the range increments.
7mm-08 Remington - Federal Fusion 140 gr. SP, MV 2850 fps, BC .390, SD .248: MPBR = 276 yards, Far Zero = 235 yards; Recoil = 14.8 ft. lbs.
.308 Winchester - Federal Vital-Shok 165 gr. TBT, MV 2700 fps, BC .450, SD .248: MPBR = 267 yards, Far Zero = 227 yards; Recoil = 17.2 ft. lbs.
The major difference between the 7mm-08 and .308 loads is in downrange bullet energy and killing power. At 200 yards (the distance at which, for consistency, I will compare all loads), the .308 Win. load generates 10.2 percent more energy and has a 29.6 percent higher KPS value than the 7mm-08 load. The heavier, larger diameter .308 bullet has more impact thump, at any reasonable range, than the 7mm bullet. No surprise there.
I view the Federal Fusion 140 grain 7mm-08 load as a heavy Class 2 game load. As a loose rule of thumb, a bullet should generate a KPS of 30 or better, at any given range, to be fully effective on Class 3 game. The killing power of the listed 7mm-08 load falls below 30 beyond 160 yards, meaning that this would not be a good Class 3 load at longer ranges.
Meanwhile, the 165 grain .308 Win. load maintains KPS scores above 30 out to MPBR range, implying that the load has adequate downrange power for small to medium sized Class 3 game.
The sectional density of both bullets (.248) is just on the cusp of what may be considered an adequate SD (.25) for bullets used against Class 3 game. The construction of the Federal Fusion bullet is specifically designed for deer-sized game, however, while the Federal Trophy Bonded Tip (TBT) bullet is designed to penetrate deeper in larger animals.
Finally, the 7mm-08 load is relatively mild mannered, generating an estimated 14.8 ft. lbs. of recoil energy in an 8.5 pound rifle, which is just under the 15.0 ft. lb. limit for recoil most hunters can tolerate without developing an accuracy degrading flinch over time. The .308 load generates about 17.2 ft. lbs. recoil (16 percent more), although many experienced shooters would likely still find it reasonably tolerable.
.280 Remington - Federal Vital-Shok 150 gr. Nosler Partition, MV 2890 fps, BC .456, SD .266: MPBR = 285 yards, Far Zero = 242 yards; Recoil = 19.3 ft. lbs.
.30-06 Springfield - Hornady Precision Hunter 178 gr. ELD-X, MV 2750 fps, BC .535, SD .268: MPBR = 276 yards, Far Zero = 234 yards; Recoil = 22.5 ft. lbs.
These calibers and loads generate solid Class 3 power (KPS above 30 at MPBR), with bullet SDs in excess of .26, to enhance penetration on large animals. MPBR distances are about 10 yards longer than the 7mm-08 and .308 Win. loads.
The .30-06 load delivers 11.8 percent greater energy and a 32.4 percent higher KPS at 200 yards than does the .280 Rem. load. The versatile and powerful .30-06 is the best non-magnum, small bore hunting cartridge, period. At 200 yards its killing power is similar to a 7mm Magnum, although it falls behind the magnum at longer ranges. However, very few hunters should be shooting at Class 3 animals beyond 200 yards with anything.
The .280 Rem. load generates 19.3 ft. lbs. of recoil, just below the 20 ft. lb. threshold between tolerable for many and uncomfortable for most shooters. The 22.5 ft. lbs. of recoil generated by the .30-06 load is 16.6 percent greater than that of the .280 Rem. load.
The .280 Remington is the neglected stepchild among the cartridges covered here. The problem with the .280 is that it is virtually identical in ballistic performance to the .270 Winchester, which was well established as a premier cartridge before the .280 Rem. was introduced. Few commercial loads are routinely offered for the .280 and even fewer production rifles are offered in the chambering. Nonetheless, anyone who owns a .280 has a very capable rifle, useful for hunting both Class 2 and Class 3 game.
7mm Remington Magnum - Hornady Superformance 162 gr. SST, MV 3030 fps, BC .550, SD .287: MPBR = 303 yards, Far Zero = 257 yards; Recoil = 23.8 ft. lbs.
.300 Winchester Magnum - Winchester Expedition 190 gr. Nosler ABLR, MV 2900 fps, BC .640, SD .286: MPBR = 294 yards, Far Zero = 250 yards; Recoil = 29.6 ft. lbs.
These are serious small bore loads, which carry lots of killing power downrange to their MPBR distances of around 300 yards. That terminal power, along with quite high bullet SDs, imply that Class 3 animals can confidently be hunted with these calibers and loads.
Comparing 200 yard power, the 7mm Rem. Mag. is quite strong, while the .300 Win. Mag. load is even stronger, with 10.8 percent more energy and a 30 percent higher KPS. Anyone who needs more power than a .300 Win. Mag. should look for a medium bore magnum. (One or another of the small bore "super magnums" will gain one only a modest amount of power and range, but with considerably more recoil and ammunition expense.)
These calibers and loads are definitely powerful at both ends of the rifle. The sustained recoil of heavy 7mm Rem. Mag. loads get into the uncomfortable range, degrading accuracy for almost everyone, while a heavy .300 Win. Mag. load could be called abusive. The 29.6 ft. lbs. recoil of the .300 Win. Mag. load is almost 25 percent greater than the 23.8 ft. lbs. of the listed 7mm Rem. Mag. load. Note that these recoil estimates are for 8.5 pound (field weight) rifles.
Purposely choosing a rifle weighing at least a pound heavier is a good idea when cartridges and loads get this punishing at the shoulder. Shoot powerful magnum rifles in small doses, as the degrading effect of recoil and muzzle blast on accuracy is cumulative.
The 7mm Remington and .300 Winchester Magnums generate ballistics and terminal power sufficient for virtually all hunting situations one might encounter in North America. These two small bore magnums are most useful for hunting elk and other Class 3 game.
Further observations and conclusions
I will start with the least significant differences within the 7mm and .308 cartridge and load pairings. The MPBR difference is a mere nine yards in all three pairings, always in favor of the 7mm cartridge. The MPBR differences across the spectrum are larger, of course, ranging from 267 yards (165 grain .308 Win. load) to 303 yards (162 grain 7mm Rem. Mag. load). All cartridges and loads will reach out as far as a prudent, responsible hunter should consider shooting at a big game animal.
The data listings and comparisons also suggest some other general observations and conclusions. First, the non-magnum cartridges are all quite versatile, in the sense that hunters can choose loads that are adequate and sensible for hunting everything from antelope and small deer to at least average size Rocky Mountain elk. Here is a summary of bullet weight ranges of common commercial loads for these cartridges:
The point is that loads can be easily matched to the game in these cartridges. For Class 2 game, such as deer, loads with 139-140 grain bullets in the two 7mm cartridges are just right, while 150 grain bullets are ideal in .30 caliber for Class 2 animals.
Heavier bullets make sense if one hunts Class 3 game, such as elk. 7mm loads with 150-162 grain bullets seem to be optimal, while 180 grain loads are proven large game performers in the .308 Winchester and .30-06.
Of course, bullet design and construction make a tremendous difference in terminal performance. Be sure to use a bullet designed and recommended by the manufacturer for the job at hand.
The .30-06 merits a bit more mention. Though over a century old, the .30-06 still sets a high performance standard for small bore hunting cartridges. It is not a fat bodied, sharp shouldered, belted cartridge, but firing 180 to 220 grain bullets, it has all the power and range that the vast majority of hunting situations require. See The Forgotten 200 and 220 grain .30-06 Loads for further information.
Common commercial load bullet weight ranges for the 7mm Remington and .300 Winchester magnums are:
I know I am repeating a point already made, but I think these two cartridges are best suited for hunting Class 3 game. Bullet weights of 150 grains or heavier are most effective in the 7mm Rem. Mag., while the heavy load capability of the .300 Win. Mag. starts with 180 grain bullets. I think these calibers are generally too much gun for Class 2 game, but reduced loads, both in bullet weight and powder charge, will serve if one wishes to use his or her elk rifle for an occasional deer hunt.
Commercial reduced recoil loads, or equivalent reloads, using 139 to 140 grain bullets for the 7mm Rem. Mag. and 150 grain bullets for the .300 Win. Mag. are more than adequate for Class 2 animals. (See Reduced Recoil Ammunition: How Effective Is It? for more information.)
A .308 Winchester has been my primary deer rifle for over three decades. I hunt Whitetail deer in the Appalachians and use 150 grain bullet loads exclusively. 150 grain loads have both adequate range and power for the hunting I do. I have never used heavier bullets, because I consider them overkill for my quarry. More recently, I have used a .260 Remington, firing 120 grain bullets, as my "light" deer rifle. It also works well.
As another example, I have two relatives who are experienced elk hunters. Both swear by the 7mm Remington Magnum for hunting elk in the high country of Colorado and Montana. These are just two examples of the capabilities of the group of cartridges and loads I have examined in this article. All six of the cartridges featured here are very good big game hunting calibers. Which one of them is, in some sense, the "best" depends on the quarry, hunting methods and the hunting environment.
Full length articles on the cartridges featured here and a great many others are available on the Member Side Rifle Cartridges page of Guns and Shooting Online. See Recommended Hunting Bullets for further information on bullets suitable for particular hunting situations.
Copyright 2018 by Gary Zinn and/or chuckhawks.com. All rights reserved.