WHICH 7MM FOR YOU?

We Americans love our .30-calibers. The .30-06 is still popular and powerful. It’s little brother, the .308 Winchester is, after the .223, America’s most popular centerfire. These days, many folks want to shoot a bit farther, so we want faster cartridges that shoot flatter. Plenty of fast .30s, but with speed comes recoil. For many, a magnum .30-caliber is too much of a good thing. And, unless we do a lot of hunting for game larger than deer, magnum .30 performance isn’t necessary.

For a generation, the default position for a fast, flat-shooting, hard-hitting cartridge has been 7mm, .284-inch. In the 1950s, while Jack O’Connor was touting his beloved .270s, other notables like Les Bowman and Warren Page were pushing the fast 7mm with its traditionally long, heavy-for-caliber bullets. Oddly, Remington’s excellent .280 Remington (1957) on the .30-06 case didn’t take off. Neither did the belted 7×61 Sharpe & Hart. Probably because of availability, it was only factory-chambered by Danish firm of Schultz & Larsen.

 

This changed in 1962 with the 7mm Remington Magnum, based primarily on Les Bowman’s wildcat design: .300 H&H case, necked down and shortened, body taper removed. Fast and accurate, Remington’s Big Seven took the world by storm. It stood for decades as the world’s most popular cartridge to wear the “magnum” suffix.

 

Even so, I always thought it was misunderstood. Even with heavy 175-grain bullets, I never thought it was more powerful than the .30-06 with 180-grain bullets. It shot flatter, and its longer bullets with higher Sectional Density penetrated a bit better. It did not kick less! Still a great cartridge. I had two exceptionally accurate 7mm Rem Mags that I hunted with extensively from about 1980 to 2000, both on Remington M700 left-hand actions.

Depending on maker, the 7mm Rem Mag was barreled with either a 1:9 or 1:9.5 rifling twist. Both twists will stabilize 175-grain bullets, but barely. Interestingly, I don’t think I ever fired a 175-grain bullet down either barrel, no idea whether either would have been accurate with then-heaviest 7mm bullets. I wasn’t using them for elk, moose, or big bears. Rather, for deer-sized game, and a variety of non-dangerous African game up to about 600 pounds.

So, when I was hunting a lot with the Big Seven, I mostly used 160 to 165-grain bullets. Great accuracy, wonderful effect on game. These bullets flew faster and shot flatter than 180-grain .30-caliber bullets…and produced less recoil.

Today, the 7mm Rem Mag has slipped in popularity; the .300 Win Mag is now the most popular magnum. With more frontal area and heavier bullets (if you wish to use them), the .300 Win Mag is more powerful, better for larger game, thus more versatile. However, with heavier bullets it kicks harder.

 

Not as popular as it once was, the 7mm Rem Mag should not be discounted. It is still the world’s most popular 7mm. Part of its problem is its market has been diluted by perhaps too many fast 7mms: Similar velocity, including 7mm Wby Mag, 7mm WSM, and 7mm RSAUM, .280 Ackley Improved, and now the 7mm PRC. Faster, including 28 Nosler, 7mm STW, and 7mm RUM.

Faster and you get into over bore capacity. Sort of like a garden hose. At some point you can increase water pressure, but you can’t get more water to come out the nozzle. In cartridges, this is not the kiss of death, but it takes more propellant for increasingly smaller velocity gains. More heat, more pressure, faster throat erosion and reduced barrel life. As a hunter, this doesn’t mean much to me; I’m unlikely to shoot enough to burn out a barrel. As a handloader, over bore capacity cartridges are limited in the propellants that can be used, so more difficult to load. For competitive shooters, barrel life is important.

 

Not a handloader, not worried about shorter barrel life? Maybe the fastest 7mms are for you. Performance is fantastic out to extreme range. The 28 Nosler has been the most popular of the Nosler family of cartridges, and both the RUM and STW have their followings. Take one step down, and you lose some performance, burn less powder, and sustain less recoil.

 

Again, the 7mm Rem Mag is the most popular, still a great cartridge. Similar in performance, the 7mm RSAUM didn’t catch on and is almost gone. Son-in-law Brad Jannenga has a 7mm WSM he loves, has taken some great animals with it. Performance much the same as the 7 Rem Mag, but in short-action. I don’t recommend it because it’s one of the least popular WSMs, getting scarce. And, like most short, fat cartridges, has feeding issues in some actions.

All fast and faster 7mms are great cartridges—I’ve used almost all of them—but the three I consider most worth considering are: .280 Ackley Improved (AI), 7mm Rem Mag, and the new 7 PRC. Gunsmith and wildcatter Parker Ackley (1903-1989) messed with just about every cartridge case that existed. His many “improved” cartridges removed body taper, sharpened shoulders, adjusted necks. His “rule” for an Ackley Improved version was that standard ammo could still be used. Thus standard .280 Rem ammo can be used in a .280 AI chamber, usually sacrificing some velocity to case expansion.

The .280 AI is considered one of his best improvements, significantly faster than its parent. A common wildcat for decades, Nosler was first to offer commercial loads, followed by Federal and Hornady. On paper, it runs about 100 fps behind the 7mm Rem Mag (2900 fps with 160-grain bullet, 2800 with 175-grain bullet). Yesterday I had my Ruger No. 1 in .280 AI on the range with handloads: IMR 7828SSC powder with 162-grain ELD-X. My load was well below suggested maximum in multiple manuals, yet it clocked over 3100 fps. Wow! My rifle has a 25-inch barrel, which helps. And there are “fast barrels” and “slow barrels.” I don’t suggest you can get that velocity from your .280 AI, suggest you don’t try. Depending on load and who’s doing the loading, the .280 AI, 7mm Rem Mag, and 7 PRC are similar in velocity, no game animal likely to notice which one its shot with.

The .280 AI has the advantage of unbelted case with more compact ammo. Disadvantage: It isn’t widely chambered in factory rifles. Bound to appeal to folks who like to be a bit different. Although the 7 PRC has taken off like a rocket, the 7 Rem Mag still has the edge in availability. Chambered and loaded by almost everyone. I haven’t owned a 7mm Rem Mag for some time, haven’t hunted with one since 2010, but it’s still common enough that test rifles come and go.

Recently, an editor asked me to do a story on a new Springfield 2020 Boundary in7 Rem Mag. I didn’t have much ammo, so I loaded up some old 140-grain Nosler Ballistic Tips with Viht 160 powder. Almost 3100 fps, average of five five-shot groups .74-inch. Don’t sell the 7 Rem Mag short. And don’t believe that a new 7 PRC will always shoot better. Also, don’t believe the 7 PRC is significantly faster. It is not. Depending on the load, the 7 PRC might be 50 to 100 fps faster than the 7 Rem Mag, no more. Again, no game animal will notice the difference.

The 7 PRC does have advantages. Based on the .375 Ruger case, the 7 PRC boasts a modern, case design: Unbelted, fatter case, shortened to increase efficiency. This reduces potential velocity but eliminates over bore capacity, increasing barrel life, and allowing the longest, heaviest 7mm bullets to be seated out, fitting into standard-length actions without intruding into powder capacity.

Extra-heavy bullets are 7 PRC’s primary advantage. It’s specified for 1:8 twist, able to stabilize today’s long, aerodynamic 7mm bullets, now up to 190 grains. The .280 AI is specified at 1:9 so, like the 7 Rem Mag, it maxes out at 175 grains (less with today’s longer “low drag” bullets). If you wanted to use heavier bullets, you could rebarrel with a faster twist. Since I didn’t own a 7 Rem Mag, not about to rebarrel my .280 AI, I got a 7 PRC.

To be accurate, two. In ’22 I bought a Mossberg Patriot with right-hand bolt. Like the rifle, loved the cartridge. Since I’m a lefty, I recently added a left-hand Flat Creek Precision 7 PRC.

I am not an extreme-range shooter. I never shot 175-grain bullets in my Big Sevens, may never shoot a 190-grain 7mm bullet. Still, I like the idea of good accuracy with high BC 175-grain bullets. Seems to increase the versatility of a fast 7mm. So far, awesome accuracy. With 175-grain ELD-X, I’ve used the 7 PRC to take several whitetails, couple of hogs, and a good bull elk. Could have done all that with my .280 AI or a 7 Rem Mag. The 7 PRC isn’t magic, but I like what I’m seeing.