Weatherby's Best Mountain Rifle: Mark V Backcountry

Mountain rifles are a breed apart. Disciples of the type are drawn to a combination of ultralight weight coupled with extraordinary accuracy—cost be darned. They know these two characteristics often make the difference between climbing high enough and shooting well enough.

Magnum cartridge performance is also valued, but magnum rifles traditionally weigh more. So semi-fast standard-size cartridges ranging from the 6.5 Creedmoor up through the .280 Ackley Improved—which provide magnum-like 7mm performance—are popular. Until now, true magnum ballistics has been a relatively unrealistic expectation in a sub-five-pound hunting rifle.

Weatherby just introduced a rifle/cartridge combination that successfully bridges the divide. The Backcountry, built on the company’s super-sleek, light, small-diameter, six-lug version of the Mark V, is initially chambered for an all-new Weatherby cartridge: the 6.5 RPM. Importantly, it’s a true 6.5 magnum that fits into svelte actions that house no other magnum.

Here’s how. RPM stands for Rebated Precision Magnum. Yep, the rim of the 6.5 WBY RPM’s case is smaller than its body, enabling it to work successfully with boltfaces too small in diameter to feed and fire traditional magnum-diameter cartridge case heads. Think of the cartridge as a stretched-out 6.5-284 Norma.

Weatherby aficionados will have noted already that a rebated rim is a departure from the legendary company’s classic cartridge design principles. And that’s just the beginning. The visually arresting double-radius shoulder is gone, too, discarded in favor of a modern, steep-angled, efficient shoulder that enables super-precise headspacing and promotes efficient propellant burn. Also, the chamber’s throat features a traditional leade into the rifling rather than the deep freebore of Weatherby yore.

Providing north of 3,100 fps with a 140-grain bullet and 3,300 fps with a 130-grain bullet, the 6.5 WBY RPM has reach. Plus, my early work with it indicates that it’s an inherently accurate cartridge.

Weatherby has introduced three initial ammo offerings: a 140-grain Nosler AccuBond rated at around 3,100 fps from a 24-inch barrel, a 140-grain Hornady InterLock at similar velocity, and a 127-grain Barnes LRX at around 3,300 fps.

Reloading dies are available from the big brands, and the 6.5 WBY RPM is a reasonably polite cartridge to handload. I’ve had good results loading 143-grain Hornady ELD-X bullets—a super-aerodynamic projectile great for maximizing one’s ethical lethal range—and Sierra’s 130-grain GameChanger, which smokes out the muzzle in excess of 3,300 fps and provides an eyebrow-raising flat trajectory inside distances of a quarter-mile or so.

Basically, the 6.5 WBY RMP is a civilized, modernized rocket of a Weatherby cartridge. And the Mark V Backcountry rifle it’s housed in is just as impressive. As I mentioned earlier, it’s built using the very light, small-diameter Mark V action. Critical to achieving that sub-five-pound weight, that action is machined of titanium, which is also a first for Weatherby.

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To further reduce weight, the stock is made of carbon fiber using a proprietary process. Its lines are sleek and distinctly nontraditional for Weatherby as well. (“Eliminating the Monte Carlo cheekpiece alone resulted in a weight reduction of nearly three ounces,” confessed Adam Weatherby, company president.)

An all-new 3D Max buttpad plays a part, too. It’s 3-D printed of a resilient, energy-soaking composite. Grinning, Adam told me, “It’s the buttpad that got us below five pounds. We were stuck an ounce or two over. With the 3D pad, we’re a half-ounce under.” The pad features an aggressive latticework-like structure, sort of a space-age version of the classic vented pads of yesteryear. I worried about its durability. Unfounded concern, as it turned out. I used the rifle for trekking-pole-type support during a four-hour climb up almost-vertical alder-choked cliffs. Even though jammed into mud, sharp rocks, and snagging roots, the pad survived without even a scar. And yes, that climb was successful. Hanging over a cliff, I put a handloaded 143-grain ELD-X bullet squarely through the vitals of a color-phase Montana high-country bear. Watch for an upcoming feature detailing that hunt here in the pages of PH.

Unlike most of its competitors offering a sub-five-pound production rifle on the market, Weatherby refused to compromise on barrel length. Chopping two to eight inches off the muzzle is an easy way to reduce weight, but it also cripples ballistic performance—particularly with magnum-level cartridges that burn a lot of gunpowder in order to achieve top-shelf velocities. The Mark V Backcountry wears a 24-inch barrel: sleek, fluted, and fit with a lovely little brake that effectively takes the edge off recoil. Each rifle ships with a thread protector, too, for hunters who don’t like the blast of a brake.

Ultralight mountain rifles, no matter how inherently accurate, come with one challenging characteristic. Because they’re so light, they’re hard for the human behind the bolt to actually shoot well. When one is sucking wind after a hard uphill push in thin, high-altitude air and muscles are trembling and adrenaline is crashing through the system in waves because a giant buck is standing right there, it can be very hard to make an ultralight rifle steady for a careful shot. Only practice and good technique can solve that, but the Mark V Backcountry offers the critical component to getting that shot off cleanly once steady, and that’s an excellent trigger. Weatherby has partnered with Trigger Tech, a rising star on the aftermarket-trigger scene, to provide go-switches for Backcountry rifles. They’re clean, crisp, and user-adjustable for a pull weight of 2.5 to 5 pounds.

Of profound importance is the sub-MOA guarantee that comes with every Mark V Backcountry rifle. It’s a ballsy move. It’s difficult to manufacture a line of rifles with ballerina-sleek stocks and actions and spaghetti-noodle thin barrels that all achieve such a notable degree of precision. Plus, the company has to be willing to back that claim up, even knowing full well that many hunters just aren’t capable of shooting super-light rifles well enough to access that precision.

In addition to the Mark V Backcountry TI (titanium action), Weatherby is offering a version with a stainless-steel action. It weighs more, but it costs $1,000 less, wears the same stock, barrel, and trigger and is still pretty darned light.

In case you’re not convinced you need Weatherby’s new 6.5 hot rod cartridge, the Backcountry is also available chambered for the .280 Ackley Improved, 6.5 Creedmoor, and other popular mountain-hunting cartridges. Even better, whispers on the wind suggest that a necked-up, .338-caliber version of the RPM is brewing. It would be the ultimate Dall sheep and mountain grizzly combo cartridge.

If you’re lucky enough to become the proud owner of a sultry, new Mark V Backcountry rifle, pick your scope and scope rings, sling, and bipod carefully. It’s all too easy to add a full two pounds of weight—a couple ounces here, a quarter-pound there—if you don’t stick with premium, mountaineering-level gear.

My favorite scope that offers long-range-compatible features paired with mountain-climbing lightness is Leupold’s VX-3i in 3.5-10x40mm with dial-up CDS turret system and Wind Plex reticle. Built on a one-inch tube, so hunters ability to dial for distance will max out around 700 or 800 yards. There’s not enough room inside the main tube for the adjustment mechanism to tilt much more than that. On the plus side, it weighs less than any scope with a 30mm tube can—around 15 ounces or less.

Whichever scope you choose, mount it in Talley lightweight rings, which incorporate a base into their one-piece design. Ultrastrong and superbly light, they’re simply the best option available for mountain rifles. Pick the lowest ring height possible and mount that scope nice and close to the barrel in order to enable the best cheek weld possible—a trait that really benefits accurate shooting, particularly with ultralight rifles.

Slings can weigh a surprising amount. Pick a light neoprene type with a rubbery inner surface that will stick to your shoulder. You don’t need to be battling a slippery sling when climbing cliffs.

As for a bipod, I highly recommend using one whenever terrain permits. The stability offered is absolutely vital to making long, difficult shots under challenging circumstances, particularly with very light rifles. However, there is only one that I consider truly suitable for a proper mountain rifle. Made in England by Spartan Precision Equipment, the Javelin carbon-fiber bipod weighs just five ounces and QD-attaches via super-strong rare-earth magnets. Carry it in your pocket or your pack and pop it into place when called for.

With a properly set up Weatherby Backcountry in 6.5 RPM slung over your shoulder, you may someday blame failure on your boots, your preseason training, your pack, or any other number of reasons, but you’ll never blame your rifle. Assuming you do your part, it will give you the best-possible chance for success in the backcountry—no matter how steep the mountains and how gnarly the conditions.