No two big game cartridges of different caliber are as similar as these two, which makes comparisons all the more interesting.
By Jon R. Sundra
One of the favorite topics for gun writers over the years has been the ".270 vs. .30-06." It's like if you haven't written at least three or four such pieces, you've not yet achieved journeyman status as a gun scribe. But there's a reason we see such articles on a regular basis. It's because so many readers own a rifle chambered for one or the other, and they're passionate about their favorite cartridge. With passion comes debate and controversy . . . and reader interest.
Perhaps second on the cartridge vs. cartridge list is the pitting of the legendary .270 Win against the .280 Rem, which to my mind is much more of an apples-to-apples comparison. Only .007 inch separates the two calibers (.277 inch versus .284 inch), and both are based on the same .30-06 case. In short, no two big game cartridges of different caliber are as similar as these two, which makes comparisons all the more interesting. They are so similar that, with a bullet of each caliber standing side by side, the human eye would have a hard time discerning which is which.
Whenever these two classic cartridges are compared, it's important to know a little about their respective histories, especially if we are to understand the rationale behind the .280 Rem, which was introduced 32 years after the .270.
There has been very little written about why Winchester chose to establish a brand-new caliber for the cartridge it introduced in 1925 in conjunction with its equally new Model 54, the first commercial bolt gun by a major manufacturer not based on a modified military action. Personally, I think choosing .277 was purely an arbitrary decision based on the fact that the Winchester folks simply wanted something different. So, instead of going with an existing caliber, they chose an oddball size that was midway between two well-established European calibers, the 6.5mm (.264 inch) and 7mm.
The .270 Win was a hit right from the start, but only with ballistically astute hunters and riflemen. You have to remember that back then, Joe Average was still a lever- rather than a bolt-action guy. But for those who were willing to make a change, here was a cartridge that launched a 130-grain bullet at a nominal 3,160 fps (since downgraded three times to the current 3,060 fps), which was impressive when compared to the one cartridge it was invariably pitted against ó the .30-06's 150-grain load, which loafed along at a mere 2,900. The latter had more recoil and did not shoot as flat or retain downrange energy as well.
The .270 Win became phenomenally popular, but not until the post-WWII era when the bolt-action rifle began its ascendancy. As a result, Winchester's prime (and only) real competitor at the time, Remington, decided they had to challenge their rival with a similar cartridge of their own. Thus, in 1957 the .280 Rem was born, a true 7mm cartridge of .284 diameter.
If Remington made a miscalculation, it was in developing the .280 for the company's Model 740 autoloading rifle, and as such could not be loaded quite as hot as the .270 Win. If truth be told, there probably would never have been a .280 Rem had they been able to chamber the Model 740 for the .270, but factory-loaded ammo was just too punishing to the action. Keep in mind that Winchester's engineers designed the .270 for use only in modern bolt-action rifles ó their own ó and was factory-loaded accordingly. They didn't have to worry about the strength of existing actions or other action types.
Anyway, Remington found that by going to the slightly larger 7mm caliber, they could virtually match .270 Win ballistics with bullets of comparable weight, and with slightly lower chamber pressures. The result was that the Remington round, as good as it was, only matched the .270's performance, and the buying public was underwhelmed. Why opt for the new .280, went the reasoning, when it only duplicated the performance of the well-established .270?
Not helping matters was Remington's introduction of its 7mm Magnum just 5 years later in 1962, which was yet another obstacle for the .280. In 1979, Remington tried to resuscitate the round by bumping up its performance a tad and calling it the "7mm-06." That, however, was misleading, because that designation implied that the .280 was a .30-06 case necked down to 7mm, which technically it was not. So, before guns and ammo even started to roll off the production lines, the name was changed to "7mm Express Rem."
After a short time, Big Green decided to go back to the ".280 Rem" designation, and since the early ë80s, the round has slowly gained popularity, especially among custom-rifle builders and handloaders, because if truth be told, it's a better cartridge than the .270. There, I've said it! I may have taken a circuitous route to get here, but I'll say it again: The .280 Rem is a better cartridge than the .270. Now, while you .270 fans are sharpening your letters to the editor pencils. . .
In a side-by-side comparison, these two rounds are very similar. As for the case on which each is based, the .270 Win is nothing more than the .30-06 necked down to .277 inch. In other words, the .270 case has the same head diameter, headspace, body taper and shoulder angle as the .30-06. The only difference is that the .270's overall case length is .046 inch longer than that of the .30-06, and it's because of the necking-down process. When you neck down, you lengthen the shoulder but shorten the neck. So to make up for the lost neck length, Winchester added .046 inch to the neck, which made the overall case length that much longer than the .30-06.
As for the .280 Rem, it's actually based upon the .270 in that it has the exact same overall case length (2.540 inch), but to ensure that Murphy couldn't force a .280 Rem round into a generously chambered .270 Win rifle, the body of the .280 (headspace), was lengthened by about .050 inch. However, the overall case length was not increased, so as a result, the .280 has a neck that's about .044 inch shorter than that of the .270 Win. Having a longer body, the combustion chamber (powder capacity) of the .280 is slightly greater ó about 2 grains more than the .270 when comparing brass of the same manufacture. Granted, that's not a lot, but it works out to about 3 percent, and 3 percent is 3 percent. As long as we're splitting hairs ó and we are when we compare these two cartridges - that translates into higher velocity, all other things equal.
When I said earlier that the .280 was the better cartridge, it's also the more versatile of the two, not only in terms of the variety of factory loads offered, but more importantly, in handloaded form, because that's the ultimate criteria of cartridge performance. Remember that .280 Rem factory ammunition is always loaded to lesser pressures than the .270 because of the many Model 740 series rifles out there. That's why making ballistic comparisons based on factory-ammo charts isn't quite fair.
But first let's address the versatility aspect. In the more common .270 Win factory loadings (and everybody who loads centerfire ammunition loads for the .270), the range of game bullet weights is 130 to 150 grains. In .280 Rem, only four manufacturers are involved - Federal, Norma, Remington and Winchester - and the weight range among their various offerings is 140 to 170 grains.
As for the common weights available to handloaders from the more popular component bullet makers, .270 game bullets start at 120 grains and go to 160; in 7mm, they start at 130 and go to 175. In each caliber, there is an exception, however, and they're from the Barnes folks who offer a humongous 180 grain in .277-inch diameter, and a 195 grain in .284 inch. Both are spitzers, I might add, rather than round-nosed.
The non-handloader, then, has readily available .270 Win factory ammo spanning 20 grains topping out at 150, while the .280 Rem man has a 30-grain span from 140 to 170. For those who roll their own, with the exception of the super-heavy Barnes' already noted, only Nosler offers anything heavier than a 150 in .270 caliber ó a 160 Partition, while there are many 7mm bullets of 168, 170 and 175 grains. Indeed, among .277-inch component bullets of big game weight, there's a 120, 130, 135, 140, 150 and one 160. In 7mm, however, one can choose from 130, 139, 140, 145, 150, 154, 160, 162, 165, 168, 170 and 175. Surely the case is made for the .280 being more versatile where both factory ammo and handloads are concerned. And if one is going to stretch either cartridge's capability by going after elk, moose, big bears or the largest African antelope, the .280 has the edge.
Now for the ballistics. Though these two rounds differ by only .007 inch in diameter, comparisons between the calibers cannot be made with bullets of the same weight; they must be made by weight relative to diameter or Sectional Density. In other words, because of its smaller diameter, a 130-grain .270 bullet is to that caliber weight-wise what the 140 is to the 7mm; the 140 in .270 to the 150-grain 7mm; 150 to 160, and so on. These ratios can be seen in the above data table comparing the Sectional Densities of these bullets.
You'll notice that none of the above SDs are identical, but they're the closest we can come, given the respective bullet weights available. Notice also that the 7mm bullets all have higher SDs than their equivalent .270.
The other criterion we need to establish here is the aerodynamic efficiency of these bullets, which is to say their ballistic coefficients, and for that to be meaningful we must compare bullets of identical profiles. In the case of the 130-grain .277 vs. the 140-grain 7mm, and the 140 vs. 150 categories, we can use Nosler's Ballistic Tips because all four bullets are offered in factory ammo. Since Nosler doesn't make a 150-grain Ballistic Tip in .270 caliber, we'll use the Partition because they do make that bullet in 150, and a 7mm in 160, so again we're comparing bullets of the same nose shape and heel profile. The "Ballistic Coefficient Comparisions" table, right, shows the respective BCs for these bullets.
Note that because the 150/160 comparison uses the less aerodynamic Nosler Partition bullets, their BCs are lower than they would be if they were Ballistic Tips. If both were available in the Ballistic Tip line, we could interpolate that, given the existing .270 Ballistic Tip's BC of .496, a 160-grain 7mm version of that same bullet would be about .510.
Using selective examples taken from among the plethora of handloading data available in both calibers, one could choose either cartridge and "prove" that it's superior to the other. So the best way to make meaningful comparisons is to use factory ammo, assuming identical bullets are being used, because factory ammo is developed in pressure barrels and loaded to SAAMI specs for optimum velocity. In the 130-grain .270 vs. the 140-grain 7mm, we find that Remington
loads both with AccuTip boattails, so let's see how they stack up. Point of Impact (POI) is based on a 250-yard zero (see table at bottom).
Unfortunately, there are no examples of factory-loaded ammunition we can use for the 140/150 and 150/160 comparisons that use identical bullets, but trust me when I say that using computer ballistic programs, where you can specify the same bullets exiting at factory velocities, the differences would be about the same as seen in the above 130/140 table. And keep in mind that all factory .280 ammo is loaded to about 2,000 CUPs lower than .270 Win fodder because of the semiauto issue. In a modern bolt-action rifle, there's no reason not to load both calibers to the same pressures. Assuming that, in handloaded form, the .280 is capable of delivering even more of a difference in terms of downrange performance. But even at that, the .280's on-paper superiority is just that academic, and of interest only to ballistic geeks like me. Don't expect to see any meaningful differences in the field, because you won't. I'm just trying to prove a point . . . and to get you .270 guys to lay down those pencils!
Reprinted from the July 2006 issue of Buckmasters GunHunter Magazine. Subscribe today to have GunHunter delivered to your home.