Field Test: Rock River Arms .450 Bushmaster LAR-15M

I’m not ashamed to admit it—I am the world’s worst free-hand shot. I can make the X-ring cringe at the range, but when the adrenaline is flowing and I’m trying to put the crosshairs on a game animal, things go sideways rather quickly if I’m not prone or on an improvised field rest. That’s why I don’t take free-hand shots at animals. But when that bruiser boar we were stalking made a surprise “course adjustment” and popped out of the brush where it wasn’t supposed to, there was no time to grab the sticks.

I pulled up, shot, missed, shot again, missed again.

The porkchops quickly disappeared into the palmettos.

Yes, the hog was moving at a good trot, but that’s no excuse. I just suck at free-hand shooting. Nevertheless, I came away from the incident with satisfaction.

A few hours earlier, I had spent some time on the range getting familiar with the new Rock River Arms’ .450 Bushmaster LAR-15M. Shooting on the bench, this rifle made the bullseyes nervous at 100 yards. Real nervous. On the flip side, the rifle gave me a distinct level of confidence I don’t often experience when combining AR-platform rifles and hunting. After all, the anemic “crack-zing” of a cycling 5.56/.223 isn’t too impressive if you’re hunting anything much larger than a coyote. The .450 Bushmaster, on the other hand, delivers a satisfying “WHUMP!”—the kind that signals to the shooter and anyone standing nearby that, yep…something is going down.

Putting that something down, though, is predicated on good shot placement. My free-hand attempt at that hog notwithstanding, the rifle and the load just felt right. If they could speak, I would’ve heard them say, “You get your act together next time and we’ll put the bacon on the ground.”

And that, really, is what the .450 Bushmaster is all about—delivering absolute results on big-game animals. In fact, the cartridge was originally conceived to be a decisive big-game hunting load capable of being fired from an AR-15 rifle. When introduced by Hornady (the cartridge) and Bushmaster (the first manufacturer to chamber the cartridge in an AR rifle), early adopters quickly discovered that here was a combination that would certainly justify the AR as a hunting firearm. With a velocity of 2200 fps and 2685 ft/lbs of energy out of the muzzle (Hornady 450 Bushmaster Custom), the cartridge leaves no question as to its terminal capabilities. And given that the heavy 250-grain projectile has a trajectory difference of 6.1 inches with a 200-yard zero (-2 at the muzzle, +4.1 at 100 yards), it is well within the kill zone for most big-game hunting ranges.

Rock River Arms has made a lot of noise this year with several new model introductions, not the least of which was the release of the RRAGE—a base 5.56 NATO rifle that brought with it a new handguard and upper receiver design that has the look of a monolithic upper assembly. When the company also announced a new rifle chambered for the .450 Bushmaster with a starting MSRP just under $1,200, the hunter in us got a bit excited.

Billed as the LAR-15M, the RRA .450 Bushmaster is designed for the shooter who wants maximum terminal performance within the 200- to 250-yard envelope in a compact and relatively lightweight platform. Since most big game hunting takes place well within that range, the LAR-15M is right in the zone.

The rifle is built on RRA’s LAR-15M forged lower receiver and pairs with the company’s A4 upper. Nothing fancy here, just solid manufacturing with the expected features in the expected places.

Leading the upper receiver is a 16-inch barrel. It’s a shorter tube than what you might expect for a specialty rifle intended to see hunting duty for most buyers, but it’s the absolute right choice for a brush gun. Compared to the more prevalent 20-inch barrels on RRA’s hunting ARs, the .450 Bushmaster is much more maneuverable in tight quarters and easier to carry when you’re running to intercept game or catch up with the dogs. And at 6.8 lbs (empty mag), it’s also downright light.

The .450 Bushmaster barrel is made from stainless-steel and is cryo-treated to maintain its shape under heavy use. To better stabilize that large and heavy bullet, the engineers selected a fast 1:24 rate of twist. With its mid-length gas system, our test rifle cycled flawlessly on the bench and in the field.

Tipping the barrel is the RRA operator brake. It seemed to work fine for muzzle management. Since hog hunting was on the menu for this trip, the fact that this brake comes with an aggressive bite gave us a bit of confidence should hand-to-hog combat be in order.

Shrouding the barrel and mid-length gas block is RRA’s latest free-float handguard. It’s quite smooth in the hand, with no integrated rails or sharp corners to cause hiccups. Being M-LOK compatible, you can choose if and where you want to put any railed accessories. Again, for hunting purposes, this makes for a clean setup.

Rounding out the .450 Bushmaster rifle’s furniture is an RRA A2 grip and Operator CAR stock. The grip is functional, but for long carry sessions, one of their more ergonomic grips—perhaps their Hogue rubber grip—would be more comfortable.

We do, though, like the stock. The Operator CAR is one of the more comfortable adjustable AR stocks out there. It has ample acreage along the top so you can get a solid, comfortable cheek weld. Additionally, the smooth contours aren’t prone to whisker-grabbing like many of the stocks out there.

Regarding recoil, I’ve heard a few people gripe about the shoulder smack. Honestly, it didn’t seem like anything to write home about. This is a highly subjective area, and everyone is different. It may cause some grown men to weep in a light bolt-action rifle, but the RRA model didn’t give me any regrets or a sore shoulder.

With my foul shots behind me, it was time to put on my let’s-get-it-done game face. Fortunately, it wasn’t long before we located a handful of hogs causing a ruckus in a small oak hammock. Centering my attention on a grizzly-looking boar, I pulled out the shooting sticks, took a good rest, and waited for a solid broadside shot. My intent was to put the .450 slug smack into the shoulder to see just what kind of knockdown the 250-grain bullet would deliver. Well, knock it down it did. Taking the 40-yard chip shot, the boar dropped where it stood and that was that.

A lot of people will argue the reason for the .450 Bushmaster cartridge’s existence. After all, there are cartridges out there that are just as capable and more so of taking big-game in an AR platform. That may be true, but if capability was the only determiner of firearm and cartridge choices, we would only have a handful of firearms and ammunition types to choose from because there would be no need for the hundreds of variations we have today.

That is not the point. The point is enjoying what you enjoy. The AR has become the iconic firearm for many shooters and hunters—particularly those who have come into the sport in the last decade or so. In conventional 5.56/.223 chamber, though, the rifle is not suitable for big-game hunting. The .450 Bushmaster, though, most certainly is for most hunting situations. Its stopping power is decisively swift, and it’s simply a fun cartridge to unleash in a properly setup rifle. Our Rock River Arms .450 Bushmaster proved that quite handily.