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The Weatherby 6.5-300 Magnum

The new 6.5-300 Weatherby Magnum is notable in a number of ways.

It is the company's first new cartridge introduction in nearly two decades. Second, it's metric, making it a standout in Weatherby's lineup. Third, it breaks existing velocity barriers for a 6.5 (.26 caliber) bullet. Fourth, it's offered in the newly redesigned and improved Mark V action, now being entirely manufactured in the USA.


Add that up and you have a new contender for a best-in-class rifle-cartridge combination for the serious long-range big-game hunter.

The popularity of the 6.5 cartridges has been centered mostly in Europe. There have been many 6.5mm cartridges introduced over the last century or more, but none have made any serious dent in the U.S. market. Perhaps the two that came closest were the .264 Winchester Magnum and the 6.5 Remington Magnum of the late 1950s and early '60s.

But despite their lack of popularity in North America, the various 6.5 cartridges have developed a reputation for long-range accuracy that surpasses the more popular .270 and 7mm (.28 caliber) offerings. This is due mainly to the high ballistic coefficients of the 6.5 bullets. With interest in long-range shooting on the upswing, we have seen the resurgence of 6.5 cartridges, among them the .260 Remington, 6.5 Creedmoor, 6.5-284, and the .26 Nosler.

It would seem that Weatherby entered the market at a perfect time, and the 6.5-300 Weatherby Mag. outclasses the others in both velocity and long-range terminal energy.


Taking a closer look at the cartridge, we see that unlike the .257 and .270 Weatherby Mag. cartridges, the 6.5-300 uses the full-length (2.825 inches) .300 Wby. case, making the 6.5-300 0.276 inch longer than either the .257 or .270. Greater propellant capacity equals more speed, thus the 6.5-300's 127-grain Barnes LRX (.485 BC) bullet screams from the muzzle at over 3,500 fps.

High velocity also translates into extremely flat trajectory. Zeroed at 300 yards, the 127-grain bullet drops less than seven inches at 400 yards. That's not all. An often-overlooked criterion in long-range hunting is terminal energy.

The 6.5-300 has that covered as well.

Its 127-grain bullet load racks up 200 foot-pounds more energy at 500 yards than the .270 Weatherby Mag. at the same distance with a 130-grain bullet. On paper, as I would not propose actually shooting a game animal at these extended ranges, the 6.5-300 Weatherby Mag. retains enough velocity (2,220 fps) and produces enough energy (1,390 ft.-lbs.) at 800 yards to still provide effective terminal performance on medium big-game species with today's premium bullets.


While paper statistics are great indicators of theoretical potential and provide lots of fodder for campfire debates, the real test comes when you take the rifle to the range and into the field.

My test rifle was one of Weatherby's newly updated Mark V Accumarks with features you'd expect on a precision hunting rifle. First and foremost in my opinion is the new LXX trigger, whose surfaces are precision ground, polished, and hand-fitted.


The LXX has a wider trigger face for greater finger contact and is adjustable down to 2.5 pounds. Mine broke crisp and clean at three pounds. Mark V Accumark barrels are stainless steel, 26 inches long (28 inches overall with muzzlebrake), fluted to reduce weight and hand lapped to a mirror finish. Barreled actions are pillar-bedded into newly redesigned hand laid composite stocks that ensure environmental stability.

All Accumark rifles are guaranteed to shoot sub-MOA 100-yard groups (0.99 inch or less), and a test target is included. The rifle I fired in Weatherby's 100-yard test tunnel produced a 0.42-inch three-shot group with the 127-grain LRX load. The average muzzle velocity across the three rounds fired was 3,510 fps.

Overall, I give the new Accumark high marks.

The stock is dark gray with a lighter gray spiderweb pattern. Refinements include thinned wrists and fore-ends, and the grip now features a slight right-hand palm swell. The rifle comes up fast and sure and is lighter than previous versions but noticeably muzzle heavy, which I find aids in off-hand shooting. I could not wait to get it out to the 1,000-yard range.

But before that could happen, I had to attend a long-range shooting class given by Mark Thompson of, who's been teaching long-range shooting for more than two decades. What impressed me most with Mark's curriculum was that it was extremely hunter friendly and did not rely on scope turret corrections, which I have found to be effective but too time-consuming in most hunting situations. Experience has shown me that when you've got about three seconds to range and make the shot having to turn turrets just isn't happening.


Instead, Mark's technique focuses (no pun intended) on a ballistic reticle he designed that sits within a proprietary Thompson Long Range Leupold VX-3 4.5-14X 40mm scope. To ensure proper scope mounting and concentricity, students are taught how to handlap and true their scope rings, and scopes are properly centered within the rings by the use of a downrange plumb bob to eliminate any possible cant. The final touch is securing a spirit level just behind the rear scope ring.

Shooters are instructed that when making shots past 300 yards to always check the level to make sure cant is not present. Mark likes to quote the Marine Corps Sniper Manual that states: "At 1,000 yards six degrees of cant moves the bullet 55 inches from point of aim." Six degrees of cant can be visualized as one minute on the face of a wristwatch€¦a minuscule amount indeed!

The Thompson Long Range Leupold's reticle has a series of crosshairs and dots. These correspond to ranges from 0 to 1,000 yards once the rifle is zeroed at 200 yards and the scope's magnification is turned up to its highest power. The main crosshair is then used for shots from 0 to 300 yards. From there, three descending dots indicate your aiming point for 400, 500, and 600 yards. A finer crosshair is below those dots and is used at 700 yards. Three more descending dots bring you out to 800, 900, and 1,000 yards. The scope setup is very straightforward, easy to comprehend, and, most importantly, fast.


Of course, the one element that a ballistic scope and accurate rifle can't overcome when shooting long range is wind. Only practice will teach you the ins and outs of reading wind, and I have found the best way to learn is to spend plenty of time shooting prairie dogs.

For avid sheep, mule deer, elk, and antelope hunters who often encounter shots at distances that are all too often uncommonly long, the new 6.5-300 Weatherby Magnum Mark V Accumark, along with a properly mounted and zeroed Thompson Long Range Leupold scope, helps even the odds. If you really want to take it to the next level, give Mark Thompson a call and attend one of his long-range shooting classes.

Taking long-range shots at big game is a question of real skill and refined ethics. It's a responsibility that should not be taken lightly. Hunters need to know what they are doing before risking a long-range shot. The right equipment and skill based on lots of practice will make the difference between a shot you'll always remember instead of one you'll always regret.

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