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Developing the .30 Newton-PRC Wildcat

What do you do with a semi-custom rifle that doesn't perform the way you want? One option is to develop a wildcat cartridge for it.

Developing the .30 Newton-PRC Wildcat

Lane’s .30 Newton-PRC wildcat (center left) bridges the modern .300 PRC and the obsolete .30 Newton (center right). It performs much like other .30-caliber magnums. (Shooting Times photo)

If you’ve read my column for a while, you know I’m fond of odd cartridges and enjoy handloading obsolete and wildcat rounds. The latest of which I’ve designated as the .30 Newton-PRC. The idea came about while I was reviewing the .300 PRC for Hodgdon’s 2020 annual reloading manual. One of the rifles included in that review was a one-off version of Montana Rifle Co.’s M1999 Extreme Tactical Hunter.

Although it would readily chamber factory-loaded cartridges, the action and magazine were approximately 0.15 inch short. That minor issue was easily overcome by single-loading factory rounds and building my handloads to 3.5 inches COL. However, the Magpul vertical-stack magazine, which was designed to accommodate five .300 Winchester Magnum rounds, wouldn’t work with .300 PRC ammo. After inserting the third .300 PRC round, the bottom round would bind so that the top two wouldn’t feed reliably. So I had a nice, semi-custom rifle marked .300 PRC that was restricted to one shot—or three shots max.

After completing the assignment, I thought about how I could remedy this situation. The easiest path was to simply rebarrel it for the .300 Win. Mag. However, I thought, “Why not pursue a new handloading challenge and chamber it for the long-obsolete but very similar .30 Newton?”

Charles Newton designed the .22 Hi-Power and .250-3000 for Savage over a century ago. He also developed a line of high-performance hunting rounds and rifles, including the .256 (actually 6.5mm caliber), .270, .30, .33, and .35 Newtons. The .30 Newton originated soon after the .375 H&H Magnum was introduced in 1912. However, unlike the .375 H&H with its belted case, the .30 Newton was beltless. But the case head diameter was almost as large as the H&H’s. Although overall length was the same as the .30-06, the .30 Newton certainly delivered magnum performance.

Unfortunately, Newton was a much better technical wizard than a businessman. His ill-fated (that’s another story) venture failed after a few years and the 4,000 or so Newton rifles now have only modest collector interest. Western Cartridge made Newton ammunition until the late 1930s, and Speer made at least one run of .270 and .30 Newton brass in the early 1950s.

I first became aware of the Newton cartridges when the .375 Ruger was introduced about 10 years ago. I discovered it was a close twin to the .375-30 Newton wildcat. The .300 PRC originated as the wildcat 30-375R (formed by simply necking down the .375 Ruger case), so I concluded the .300 PRC was a close twin of the original .30 Newton.


Hornady’s 6.5 PRC and .300 PRC share several important design features. First, the beltless case head and rim are the same diameter as typical large-caliber belted magnums. Second, there’s minimum body taper and a relatively sharp shoulder. Third, and likely the most important, the chamber throat and leade are sized to allow seating a bullet out farther to maximize case capacity and closely align it with the bore axis. All three features tend to enhance the PRC’s performance.

So I asked myself, “Why not rebarrel the Montana rifle and chamber it for the old Newton cartridge?” To ease the conversion, I incorporated two minor differences from the .300 PRC cartridge/chamber criteria. I retained the PRC case head/rim dimensions (about 0.006 inch larger diameter than the .30 Newton) and duplicated the PRC’s critical throat dimensions. That allowed fully utilizing the rifle’s magazine COL limit, maximized case capacity, and ensured optimal bullet-bore alignment.

Dave Manson of Manson Reamers agreed to make the necessary reamers, and I asked him to retain the .300 PRC’s case head diameter and add 0.020 inch to the neck length since the parent case was long enough to do so.

Robin Sharpless at Redding Reloading provided the custom dies, and reforming the parent brass was accomplished with only a few mishaps. I discovered that the reformed cases held 8 percent less water than fired .300 PRC cases. Using load data from my earlier .300 PRC report, I calculated how much to reduce the original charges.

I now have a rather unique but fully functional and capable rifle suitable for hunting most North American big game. You definitely won’t find one like it at your local dealer’s shop.

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