May 24, 2023
The 7mm caliber sits in the sweet spot for any rifleman. It’s a big enough diameter that the bullet weight can handle any game in North America, and those same bullets will kick up enough dirt to spot misses on steel targets at distances exceeding 2,000 yards. It’s also possible to send heavy-for-caliber bullets with superior aerodynamic properties at around 3,000 feet per second (fps) without exceeding 65,000 pounds per square inch (psi) of chamber pressure — and without generating abusive recoil. The 7mm is ideally positioned to offer the perfect combination of ballistic performance, velocity and low recoil for today’s hunter and long-range precision rifleman. Until now, only handloaders with custom-built rifles could access this divine combination.
Hot, Nasty Speed — and BC.
“The 7mm PRC doesn’t do anything my (insert pet cartridge here) doesn’t do already!” That will be the most common reply from a rifleshooter who hates anything new. The next most common statement we’ll hear is, “It’s just marketing hype!” That one will come from the edgy crowd who likes to push bias for a particular cartridge. The truth is that the new 7mm Precision Rifle Cartridge (PRC) is the only factory-loaded 7mm Magnum designed for use with Very Low Drag (VLD) bullets while still keeping the bullet’s bearing surface above the neck-shoulder junction. This, all while keeping a 3.34-inch overall length so that it will fit in everyone’s long action. This simple design philosophy is why the 7mm PRC outperforms all other 7mm cartridges.
The 7mm PRC is designed for use with VLD bullets because those are the most in-demand bullet type on the market. VLD projectiles are long, heavy and have great ballistic coefficients (BC). The high BC means the bullet resists the effects of the wind well and that it retains velocity and energy across long distances. The 180-grain ELD-M bullet features a G1 BC of .796 and a G7 of .401. The 175-grain ELD-X has a G1 of .689 and G7 of .347. Hornady has announced a 160-grain all-copper CX bullet for the Outfitter line, which will have a G1 of .596, but it was not yet available for review at the time of this writing.
VLD bullets are trending because the consumer’s understanding of ballistic advantages has improved. When the 7mm Remington Magnum hit the market in 1962, American riflemen were enthusiastic for speed. However, 7mm bullet weights topped out at about 162 grains, so BC remained low. While these bullets start out fast, they shed velocity quickly, along with the ability to deliver energy on target. Debuting in 2001, the 7mm Winchester Short Magnum (WSM) suffered from the same issue.
Also introduced in 2001 was the 7mm Remington Ultra Magnum (RUM), which had the largest case of any 7mm magnum. Appearing in 2015, the .28 Nosler came from a shortened 7mm RUM. Both are fine cartridges that cater to the crowd who feel that a bigger case with greater powder capacity is better. The problem, however, is the difference between case capacity of an empty case and usable case capacity of a loaded cartridge. This difference becomes significant when loading the VLD bullets that just about everyone wants to shoot.
Any discussion of the new 7mm PRC will compare it against the .28 Nosler and 7mm RUM, where the 7mm PRC has the lowest case volume, so expect a lot of chatter about that. Throw a powder charge in the case and seat a bullet, and the usable case capacity suddenly becomes irrelevant. Consider this: The Proof Research Tundra ($7,799, proofresearch.com) in 7mm PRC that I used for testing had a 26-inch barrel that pushed Hornady’s 175-grain ELD-X bullet at 2,981 fps. Once that rifle has some 120 rounds down the barrel, that velocity will be more than 3,000 fps. The .28 Nosler pushes a 175-grain Accubond at 3,125 fps from a 26-inch barrel while the 7mm RUM sends a 175-grain bullet out of a 26-inch barrel at 3,025 fps. Additionally, the 7mm Remington Magnum has a factory-listed velocity for a 175-grain bullet at 2,860 fps. The 7mm PRC, when loaded with a VLD, matches the velocity of 7mm RUM and is 100- to 125-fps slower than the .28 Nosler.
While the additional speed is tempting to favor, the 7mm PRC has the priceless attribute of keeping the VLD bullet out of the powder column in a loaded cartridge. Both the Nosler and the RUM — as well as the 7mm SAUM when loaded at 2.95 inches or shorter — push a lot of the bullet down into the powder column on a loaded round. When that powder ignites, the pressure from the burning powder and expanding gas can (and will) push the bullet off-axis, forcing it to yaw before engraving it to the bore’s rifling. If the bullet yaws, once it engraves in the rifling, the center of gravity forcefully relocates from where it is supposed to be to somewhere else. In extremes, the uneven ignition and push from the igniting powder surrounding a bullet can bend the bullet before it enters the bore. This potential yaw and getting bent before engraving in the rifling are not conducive to great accuracy.
A Case Study
The 7mm PRC case design has a number of features that further separate it from every other 7mm magnum round. Keeping the bullet out of the powder column also means the bullet’s bearing surface stays above the case’s neck-shoulder junction. No other factory-loaded 7mm magnum can make this claim. It’s an important consideration for the reloader who desires the lowest possible velocity extreme spreads (ES) and standard deviation (SD). Reloading a piece of brass can cause brass to accumulate at the neck-shoulder junction, creating uneven neck tension on the bullet. When fired, uneven neck tension requires inconsistent case pressure to get the bullet moving. This manifests as a higher velocity spread and deviation.
While the 7mm PRC does a great job of bullet location relative to the rest of the case, the case volume is not accidental. Hornady started with the goal of 3.34 inches as overall length with VLD bullets seated correctly in the case. The final piece was to ensure that case had an ideal volume.
More is not better when designing a rifle cartridge case. The goal with a cartridge case is to select the powders that are desirable and then build the case around the powder with the goal being close to 100-percent case fill when at maximum chamber pressure. Hornady selected Alliant Powder’s Reloder 26 and Hodgdon’s H1000 and Retumbo as the three preferred powders for the 7mm PRC, and then sized the case to be nearly full when at max pressure. This is why the 7mm PRC case doesn’t have a rebated rim such as on the .28 Nosler, 7mm RUM or 7mm SAUM. Using a rebated rim and wider case body would have only added excess volume that gave a lower percentage case fill.
Getting the case filled to ideal capacity with selected powders isn’t important when shooting targets out to several hundred yards because small velocity variations don’t matter much at those distances. When target distances exceed 1,000 (or even 2,000) yards, percentage of case fill becomes an important factor since it’s linked to velocity spread and deviation. If there’s too much empty space in the case, the powder can be crowding the bullet on one round and then back around the primer for the next. This introduces an unwanted variable when the powder ignites.
Sometimes riflemen will talk about a cartridge being “efficient” without really knowing what that means. Percentage of case fill with selected powder at a targeted chamber pressure is a fantastic efficiency metric, and Hornady nailed it.
The first two loads available for the 7mm PRC are going to be Hornady’s 175-grain ELD-X and the 180-grain ELD-M. The bullets look the same, but there are crucial differences that influence what the bullet does once it hits the target. The ELD-X bullet has a larger internal cavity under the polymer tip that promotes expansion once the tip hits the target. Additionally, the ELD-X has a noticeably thicker jacket with an interlock to prevent the jacket from separating from the lead core when impacting at high velocity.
The ELD-M has more traditional match characteristics, and it has a small internal cavity behind the polymer tip. The sizes and shapes of the cavities in both bullets are not accidental. While the ELD-X bullet cavity’s size and shape promote expansion, the ELD-M cavity’s size and shape ideally position the bullet’s center of gravity to stabilize flight for long distance. The ELD-M also has a thin jacket that makes it easier to guarantee bullet concentricity for optimal accuracy.
I tested both loads through a Proof Research Tundra rifle by firing three-shot groups at 100 yards. Performance was exceptional. One important aspect I noted about the 7mm PRC was the recoil reduction when compared to the large .30-caliber magnums. Not only will the 175- to 190-grain bullets have better BCs than the heavy end of the .30-caliber spectrum, the 7mm PRC pushes bullets faster with about 30-percent less recoil. The Tundra rifle I used for testing only weighed about 7 pounds. I was never uncomfortable while shooting it.
The 7mm PRC promises to bring new excitement to 7mm enthusiasts who appreciate the caliber’s high BCs, great velocity and low recoil. We now have a factory-loaded 7mm magnum that’s designed for maximum efficiency with VLD bullets. The 7mm caliber has a bunch of committed supporters, and I believe those ranks are about to increase.
Proof Research Tundra
- Type: Bolt action
- Cartridge: 7mm PRC (tested)
- Capacity: 4+1 rds.
- Barrel: 26 in.; 1:8-in. twist
- Overal Length: 46.5 in.
- Weight: 7 lbs., 4 oz.
- Stock: Proof Research, carbon fiber
- Length of Pull: 13.75 in.
- Finish: DLC, Cerakote
- Trigger: TriggerTech
- Safety: Two-position selector
- MSRP: $7,799
- Manufacturer: Proof Research, 406-756-9290, proofresearch.com
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