.300 PRC Reloading Data: Best Practices

Of the many .30 caliber magnums, the newish .300 PRC is the easiest to handload for optimal long-range performance on targets and for extended-range hunting alike—which is what Hornady intended. The easy-loading characteristic is thanks to its chamber throat dimensions, overall case design and generous head height. This makes the cartridge ultimately compatible with even the longest, sleekest bullets and is a huge deal for extreme-range shooters.

For those unfamiliar with the term, “head height” indicates the length from the case mouth to the tip of the bullet. A short head height forces handloaders to seat long, heavy bullets deeply into the cartridge case—the bullet’s shank intruding into propellant capacity. Worse, many of the best long-range bullets aren’t even usable in cartridges with short head height because their long, sleek ogive taper from the tip to full diameter is too long. When these bullets are seated deeply, the case mouth hangs over that taper.

The .300 PRC’s long head height enables handloaders to seat long, sleek bullets way out. To provide enough head height for extreme long-range bullets, Hornady’s design gurus made the .300 PRC’s case about the same length as a .30-06 or .300 Win. Mag., but they spec’d the cartridge for full-magnum-length actions. As a result, the .300 PRC is compatible with super-high ballistic–coefficient projectiles such as the 250-grain Hornady A-Tip and the 245-grain Berger Extreme Outer Limits.

A second characteristic that makes the .300 PRC easy to handload for optimal long-range performance is that it’s not over-bore. While it has plenty of propellant capacity to drive even the heaviest projectiles at useful speeds. It’s just not so rocket-like that it’s finicky by nature. As a result, the .300 PRC typically provides consistently small standard deviations in velocity, and it tends to be very accurate. And because it’s not burning excessive quantities of powder, it offers reasonable barrel life.

While I typically like to use match-quality reloading dies with a micrometer-type seating stem for long-range precision, I’ve also loaded a lot of half- to three-quarter-m.o.a. ammo using a basic set of Hornady Custom Grade dies, which were all that was available when I first began working with the cartridge.

As I write this, there are at least three different companies manufacturing .300 PRC brass. To date all of my .300 PRC handload work has been using Hornady cases, with great success. More recently, Atlas Development Group and Lapua have begun manufacturing cases. Both should be superb.

Because I’ve been primarily loading for a hunting rifle, I haven’t bothered with weight sorting and neck turning cases or uniforming flash holes. Results have been darned good anyway, which is a testament to the quality of Hornady cases and the easygoing nature of the .300 PRC cartridge.

Prime with magnum caps. I’ve used several different brands in the .300 PRC, but Federal’s 215 Gold Medal primer has provided the tightest extreme spreads and smallest standard deviations in nearly every case.

As the .300 PRC’s parent company, Hornady has the most comprehensive load data. If you haven’t already done it, download Hornady’s reloading app. Use it to select an appropriate propellant for the bullet weight you intend to load.

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Technicians from Hornady and Barnes both recommended, among other powders, Reloder 26. It’s temperature-stable and produces some best-in-class velocities. For whatever reason, H1000 is more accurate in my rifle. I’ve received outstanding velocity and accuracy with every bullet I’ve tried over H1000, so it’s become my go-to propellant for hunting-weight bullets in the .300 PRC.

For very heavy-for-caliber projectiles, like the 245-grain Extreme Outer Limits and the 250-grain A-Tip mentioned earlier, slow-burning powders such as Retumbo and IMR 7828ssc often produce best velocity combined with excellent accuracy.

When picking a projectile for the .300 PRC, the world is your oyster. You can push 150- and 165-grain deer bullets really fast. As in, 150-grainers at 3,500 fps and 165-grainers at 3,300 fps. But those bullets aren’t optimal in the .300 PRC. To achieve the performance level the cartridge is designed to reach, pick a sleek, aerodynamic bullet of 175 grains or more. The really good stuff for hunting starts at 200 grains and goes up to about 230 grains. For extreme-range target work, opt for 230- to 250-grain projectiles.

For a factory-ammo comparison load, my Proof Glacier Ti shoots Hornady’s 212-grain ELD-X factory ammo beautifully, averaging 0.64 inch. In handloads, every single bullet I’ve tried averaged less than three-quarter m.o.a. The accompanying chart shows specifics.

When it comes time to finesse seating depth, use an overall length chamber gauge to determine just how long you can leave your chosen projectile protruding. Measure your magazine box’s maximum length so you know its limit. Seat “hard” bullets—such as the Barnes LRX—at least .020 inch from the leade, with .050 inch usually being better.

Match bullets and classic thin-jacketed cup-and-core hunting bullets often give the best accuracy when seated to just touch or even lightly engrave on the rifling leade. However, avoid this with hunting loads because you don't want to get a bullet stuck in the rifling.

Even with the .300 PRC’s generous head height, some heavy extreme-BC bullets are just too long to be seated close to the rifling leade and still fit into the magazine. If you really want them seated to kiss the rifling, plan to single-load them. However, in most cases, you can seat them .015 inch shorter than the internal magazine length and still get great accuracy.

Experiment with powder types and charge weights and with seating depths just as you would when fine-tuning handloads for any other cartridge. I’ll wager that you’ll find it easy to achieve excellent precision. Assuming a well-built rifle with a quality barrel, the .300 PRC is one very accurate cartridge.