January 25, 2023
By Layne Simpson
Taller than the 6.5 PRC and shorter than the .300 PRC, the new 7mm PRC is the Mama Bear of Hornady’s extremely successful Precision Rifle Cartridge family. Maximum cartridge lengths are 3.090 inches for the 7mm PRC, 2.955 inches for the 6.5 PRC and 3.700 inches for the .300 PRC. Respective maximum case lengths are 2.280 inches, 2.030 inches and 2.580 inches. All are descendants of the .375 Ruger case which, as you may recall, was a joint-venture design development between Hornady and Ruger. Going with the same rim diameter as the .300 Win. Mag. and other members of the Holland & Holland belted magnum family simplified rifle production.
Hornady is loading 7mm PRC Precision Hunter ammunition with the 175-grain ELD-X at 3,000 fps and match ammo with the 180-grain ELD Match at 2,975 fps. Both have already proven to be extremely accurate with Precision Hunter often delivering the same accuracy as Match from some rifles. SAAMI released cartridge and chamber drawings for the 7mm PRC in June 2022. Maximum average chamber pressure was set at 65,000 psi with a velocity of 2,950 fps for a 180-grain bullet. A rifling twist rate of 1:8 is recommended. Minimum chamber throat diameter is 0.2846 inch, a mere 0.006 inch larger than the nominal diameter of 7mm bullets.
A minimum chamber neck diameter of 0.318 inch is only 0.004 inch larger than the necks of Hornady ammunition I measured. Those close fits, often seen in precision-built target rifles with minimum-dimension chambers, assure precise alignment of bullet and bore axes, and that goes along way toward a level of accuracy required to win matches.
Load data received from Hornady and Hodgdon show slow-burners such as Alliant Reloder 26, Vihtavuori N-560, Winchester StaBall HD, Ramshot LRT and Hodgdon Retumbo ranking high among a number of propellants producing the highest velocities with bullets ranging in weights from the Hornady 139-grain InterLock SP to the Berger 195-grain Elite Hunter.
Maximum velocities from 24-inch barrels are listed as 3,350 fps for the former and 2,871 fps for the latter. Magnum primers were used. This article was written prior to the official launch of the cartridge, but by the time you read this, Hornady will have published loading data. Hodgdon is slated to have loads for its various powders in its next annual manual, which will be available January 2023.
For six decades the 7mm Rem. Mag. has ranked extremely high in popularity among hunters, and it has occasionally been seen in the hands of long-distance competitive shooters as well. In addition to being capable of delivering excellent accuracy, it is powerful enough to handle most big-game animals on the planet at a level of recoil easily tolerated by experienced hunters. The reason I mention a Remington cartridge in a report on a Hornady cartridge is because when performance is compared, they are peas of the same pod. Here is why.
7 PRC vs. 7mm Rem. Mag.
I compared the gross capacity of primed Hornady PRC cases with 7mm Rem. Mag. cases by weighing them on a digital scale and then weighing them again after they were filled to the brim with water. The averages were 80.4 grains for the Hornady cases and 82.7 grains for the Remington cases. A net capacity comparison is more meaningful, so I seated the Hornady 180-grain ELD Match in the 7mm PRC case at a cartridge length of 3.290 inches which duplicated the length of Hornady ammo loaded with that bullet.
The same bullet was seated in the 7mm Rem. Mag. case for a cartridge length of 3.440 inches. That positioned the bullet 0.020 inch shy of contacting the rifling when the dummy cartridge was chambered in a fairly new Model 700 rifle with only a few rounds through its barrel. Net capacities were 68.5 grains for the 7mm PRC and 72.9 grains for the 7mm Rem. Mag. For cases of their sizes, the small difference in capacity has virtually no bearing on the difference in velocity potential. I mention all of this not to put down the 7mm PRC but to point out that Hornady has done a great job of giving many of today’s hunters and competitive shooters what they have long been asking for: a non-belted version of the time-proven 7mm Rem. Mag.
“The 7mm PRC was designed to strike the balance between the smaller, lighter recoiling 6.5 PRC and the much larger 300 PRC,” Hornady’s Seth Swerczek told RifleShooter. “We put shootability, precision and efficiency at the forefront. This is the first 7mm cartridge that has the appropriate SAAMI overall length and twist rate to take advantage of the ultra-sleek, low drag bullet options that today’s hunters and shooters want to use. Because of its design attributes, shooters now have a factory available option that can perform in long-range match settings or on nearly any big game hunt with equal aplomb,” he said.
As he mentioned, the bullet aspect is certainly one advantage over the 7mm Rem. Mag. The rifling twist rate of the barrels of most factory-built rifles in 7mm Rem. Mag. is too slow to stabilize the new breed of finger-long bullets such as the Hornady 190-grain A-Tip Match and the Berger 195-grain Elite Hunter. Another advantage in favor of the 7mm PRC is a considerably longer chamber throat in rifle barrels that allows uncommonly long bullets to be seated with minimal encroachment on the powder cavity of the case. Having a custom rifle built in 7mm Rem. Mag. will make the two differences go away, but as off-the-shelf factory rifles go, the 7mm PRC is the clear winner.
As this is written, I have enjoyed shooting the 7mm PRC in three different rifles. The first, a Model 700 built by RemArms, did a great job of whacking steel targets out to 1,400 yards at FTW Ranch in Texas, home of the SAAM shooting school. Next was a 20-pound rifle with a heavy, 30-inch barrel built by H.S. Precision for long-range competitive shooting. I have not had an opportunity to try it on steel but on paper it has shot everything I have fed it—including the two Hornady factory loads—inside a half inch at 100 yards for five shots, with several handloads crowding quarter-minute accuracy.
The Mossberg Patriot Predator chambered in this cartridge was nowhere near that accurate, but considering its price, groups were small enough to cleanly take game as far away as I care to shoot. I look into my crystal ball and see many other rifle builders hopping aboard the Hornady 7mm PRC express.