The RCMs are essentially short versions of the 2.580-inch-long .375 Ruger. They share its .532-inch head and base diameter. In contrast, the Winchester Short Magnums have a .535-inch head (which still works on the .532-inch bolt face standard for belted magnums). The WSM features a rebated rim; body diameter starts at .555 inch.

"WSM magazines accommodate RCM cartridges just fine," says Mittelstaedt. "But the smaller RCM body diameter lets you stuff four rounds in magazines designed for three WSMs."

Hornady's .300 and .338 rounds, both with 30 degree shoulders, measure 2.100 and 2.015, base to mouth. They're both loaded to an overall length of 2.840 inches. The .338 hull is shorter (.308 Winchester length) to accommodate a variety of .33-caliber bullets, most of which were designed for the .338 Winchester Magnum. A 68-grain case capacity runs 4 grains shy of that for the .300 RCM (water, to the case mouth). Capacity of the .300 falls halfway between the .30-06 (67 grains in Remington brass) and .300 WSM (79 grains in Winchester cases). Mittelstaedt tells me the necks on both cartridges measure very close to .300.

"We developed the RCMs in Ruger M77 Mark IIs that we barreled here," Emary explains. He deflects any question as to Ruger's planned use of the cartridges. "We're still tweaking propellant types and charges. Getting target speeds from short barrels isn't as simple as it may sound, but we're very pleased with results so far."

My introduction to the Ruger Compact Magnums came last August, when I managed to snare one of the test rifles in .300 RCM. It featured a 24-inch barrel and recoiled about like a .30-06. The cartridges fed smoothly--more smoothly than a .300 WSM, it seemed. I soon ran through a limited supply of ammo. My best groups prone measured an inch and a half. A week later, after the barrels on this rifle and a .338 RCM had been lopped to 20 inches, I collared Ken Oehler and sneaked off to a nearby range. After he set up one of his fine chronographs, I laid the .300 RCM across a Lead Sled and, to my delight, printed a 1-inch group. A second trio of 180-grain SSTs clocked 2,845, 2,846 and 2,847 fps. Such consistency is rare.

As the .300 cooled, I benched the .338 RCM and punched a group spanning 11⁄4 inches. The 35P chronograph showed velocities ranging from 2,663 to 2,696 fps, with a mean of 2,678. Another string averaged 2,698--essentially what a .30-06 gives you with 180-grain factory ammo at claimed velocity (which seldom shows up on the chronograph). Despite its abbreviated barrel, the M77 Mark II in .338 RCM was civil in recoil and a lot more pleasant to shoot than a .338 Winchester Magnum. Ballistically, it falls shy of that belted .33 and the .325 WSM. How much shy depends on barrel length. You get about 2,800 fps from a 225-grain spitzer from the two bigger cases in 24-inch barrels. In a 20-inch tube I'd expect them to clock under 2,700.

What's up next for Hornady? Rumor has it that new LeverEvolution loads for the .32 Special and .44 Magnum will be ready before you read this. Makes you wonder if those trolls in Grand Island ever break for hunting season.