August 10, 2023
It could be argued that the origin of the modern precision rifle cartridge was in the late 1970s when Dr. Louis Palmisano and Ferris Pindell created a cartridge and named it the 6 mm PPC. It was based on the .220 Russian cartridge. Palmisano and Pindell reduced the body taper of the case, gave it a 30-degree shoulder, and necked it up to 6 mm. It became very popular for benchrest competition, and some have gone so far as to claim it the most accurate centerfire rifle cartridge ever created.
About 45 years later, Hornady introduced the 6 mm ARC cartridge. The 6 mm PPC and the 6 mm ARC are dimensionally very similar. The primary difference is that Hornady specified a rifling twist rate of one turn in 7 1/2 inches for the 6 mm ARC. While the 6 mm ARC (Advanced Rifle Cartridge) is not in Hornady’s PRC family, it emulates the design parameters of the PRC cartridges and what many consider the concept of the modern precision rifle cartridge.
All Hornady PRC cartridges have a 30-degree shoulder, minimum body taper and optimized case length, and they call for fast rifling twist rates that will support bullets with high ballistic coefficients. But I’m getting ahead of myself. While the 6 mm PPC might be considered the foundation of the modern precision rifle cartridge, and while the 6 mm ARC might be its ultimate expression, the cartridge that crystalized the modern precision rifle cartridge movement was the 6.5 Creedmoor.
ENTER THE CREEDMOOR
In 2008, Hornady introduced the 6.5 Creedmoor. It was conceived as a long-range competition cartridge and is very similar to the .260 Rem. The difference lies with their parent cases. The .260 is based on the .308 Win. with its 20-degree shoulder and requires a 1:9 rifling twist. The 6.5 Creedmoor is based on the .30 TC cartridge, which has a 30-degree shoulder, less body taper and is slightly shorter. These differences, combined with a faster 1:8 twist rate, allows factory 6.5 Creedmoor rifles and ammo to outperform factory .260 Rem. rifles and ammo at distance.
The Creedmoor’s initial reception was sort of ho-hum. It wasn’t until after the “American Sniper” movie in 2014 that the 6.5 Creedmoor began its climb to stardom. That movie propelled the interest in long-range precision shooting, and the Creedmoor’s ability to deliver flat, wind-bucking trajectories, with minimal recoil, pushed it to the forefront. What the 6.5 Creedmoor lacked was power. That’s where Hornady’s PRC cartridge line came in and firmly established the design parameters of the modern precision rifle cartridge.
To capitalize on the Creedmoor’s success, in 2017 Hornady created another 6.5 mm cartridge with a faster velocity. Engineers took the .300 Ruger Compact Magnum case and necked it down to 6.5 mm. Loaded to 65,000 psi, and with a specified twist rate of 1:8, the 6.5 PRC could launch a 147-grain bullet to 2,900 fps, giving it a 200-fps advantage over the 6.5 Creedmoor. While this sounds like a lot, it’s only about a 7 percent increase, and in truth only extends the maximum practical range of the Creedmoor by about 100 yards.
The 6.5 PRC has found moderate acceptance, but it is in direct competition with the 6.5 Creedmoor and now the new 7 mm PRC. If, like most hunters, most of your shots are inside 300 yards, the extra expense of ammunition and added recoil from the 6.5 PRC hardly justifies its minimal ballistic gains. On the other hand, it does offer a bridge between the 6.5 Creedmoor and traditional 7 mm and .30-caliber magnum cartridges.
In 2018, Hornady introduced the military-inspired .300 PRC, which was based on the .375 Ruger case. The .300 PRC is a beast; it’ll push a 212-grain bullet to 2,860 fps and outperform the .300 Win. Mag. and .300 Wby. Mag. Due to its modern precision rifle cartridge design, it will better handle bullets with higher BCs, and this makes it a better long-range option. Being the powerful cartridge it is, recoil can be intense. The .300 PRC will generate nearly twice as much recoil as the 6.5 PRC, but it will not get a bullet to 1,000 yards any faster.
7 MM PRC
In late 2022, Hornady introduced the 7 mm PRC, which by any measure is the best hunting cartridge of the three. Firing a 180-grain bullet at an instrumental velocity of 2,980 fps, it has a 150 to 200 fps advantage over the 7 mm Remington and Weatherby magnums. As with the 6.5 Creedmoor and 6.5 PRC comparison, the increase in maximum practical range in yards equates to about 50 percent of the velocity increase in fps. However, because it can handle higher BC bullets, as the distance increases, so does the advantages of the 7 mm PRC.
While the 7 mm PRC is a highly modified .300 PRC case, as with the other PRC cartridges, it has a 30-degree shoulder, slight body taper, specified fast twist rate and is of a length that optimizes the use of long bullets with high BCs. It could be argued that if reach and power are what a hunter needs most, the 7 mm PRC offers the best balance of any of our current hunting cartridges, especially when recoil is considered. It’s suitable for any non-dangerous big-game animal anywhere in the world, and at any distance any hunter has any business shooting.
MODERN PRC ADVANTAGES
What advantages do the sharper shoulder angle, minimal body taper, optimized case length and specified fast-twist rifling really offer? The sharper shoulder is thought to help with precision, mostly due to cartridge alignment inside the chamber. It also reduces case stretching, which is something handloaders appreciate. As for the minimal case taper, optimized case length and fast-twist rifling, this allows for the use of bullets having higher BCs without excessively increasing the length of the action. And bullets with higher BCs deliver better velocity retention and less diversion in wind.
Modern precision rifle cartridge design could mostly be described as the refinement of the cartridge case, paired with faster rifling twist rates. After years of creating and using metallic rifle cartridges, engineers have just figured out ways to make them better. Granted, the advantages these cartridges offer are small, but they are advantages.
WHICH PRC FOR YOU?
The 6 mm ARC and 6.5 Creedmoor are not PRCs, but they might as well be. From the standpoint of design parameters, they share the sharp shoulder, minimal body taper, optimized case length and specified fast twist rates of the PRC cartridges. If you want to hunt with an AR-15, the 6 mm ARC is the only answer. With an AR-10, the 6.5 Creedmoor is the one for you.
When it comes to bolt guns, for shots on pronghorn- to deer-sized game inside 500 yards, the Creedmoor or 6.5 PRC will work. For greater distances or bigger critters, the 7 mm PRC is the way to go. I expect it will greatly cut into the sales of the 6.5 PRC; it’s that much better. Right now, you can buy a Mossberg Patriot Predator in 7 mm PRC for less than $500. That’s a steal, and the one I have is lights-out accurate. What about the .300 PRC? I’m not sure any hunter of non-dangerous big-game needs that much gun, especially when its advantages over the 7 mm PRC appear greater on paper than in the field.
- This article was featured in the August 2023 issue of Game & Fish Magazine. How to subscribe.