The R-15 And The .30 RAR
September 23, 2010
Remington hasn't been in the AR game very long, but it sure has made a colossal impact, bringing the black rifle to a whole new audience. In another bold move, Big Green upped the ante with an ingenious cartridge and rifle combination that harnesses .308 Winchester ballistics in the lightweight and wieldy R-15.
Everyone has his own perceptions of the .223 Remington in the AR platform by now. It simply rocks on the prairie dog fields, and it's perfect for whacking dastardly predators. But as an ever-increasing number of ARs head to the hunting fields, they are being used to fill greater roles than they were ever intended.
For a meat-seeking sportsman, unless you're into head-shooting or blood-tracking medium-bodied big game like whitetail deer, antelope, or wild boar, you probably know that the .223 isn't really the ideal cartridge to use to harvest these animals. Regardless of its high velocity and excellent accuracy, where the small-bore .223 cartridge may well excel in the varmint and predator fields, it falls distressingly flat in terms of sheer knock-down power on larger game.
Suffice to say that the 6.8 SPC and several other newer AR-15 chamberings pack a little more punch to take down larger game. But within the AR world, real confidence in this arena can only be achieved by stepping up to the AR-10 and the eminent energy of the .308. Unfortunately, that confidence comes at the cost of size, recoil, and at least a pound more weight than the smaller AR.
Filling The Gap
As you likely know by now, Bushmaster, Remington, and DPMS--in addition to several other arms manufacturers--were all acquired within the last three years by a private equity firm. They were amassed under the "Freedom Group" moniker.
At the annual Remington editorial seminar last October, those companies were all present. We were introduced to both a new cartridge and a new take on the AR platform that turned your humble narrator into a slack-jawed drooler, pondering in bewildered amazement.
Through a joint effort, the Freedom Group introduced something that was revolutionary to me. They came up with a cartridge that would fire in a cleverly reengineered AR-15 and could rival the .308 Winchester within the overall length of a .223. This was something that should put down mid-sized game in a snap.
Excited? Who me; the guy who knows quite well that .223 on a big, naturally armored boar takes nothing less than a well-placed shot in the ear or neck? I was far more than merely intrigued.
Just a few, short years ago, we were introduced to the 6.8 SPC cartridge. It was commonly touted as the end-all cartridge in the AR platform. In coordination with specialized units of the U.S. military, Remington developed the 6.8 SPC, basing it on the century-old .30 Remington cartridge. Loaded with a 115-grain projectile, it was able to produce nearly twice the energy from the shorter-barreled M4 rifle than the .223 Rem. could muster. And it fed from a standard USGI magazine with only a slight reduction in capacity.
It was exactly what the U.S. SOCOM wanted. But with its decades of experience in the whitetail woods, Remington wasn't about to label the 6.8 SPC the ultimate short-action prescription for your deer-hunting affliction. The quest to fill that ticket--specifically for the lightweight and well-balanced AR-15 hunting platform--was just beginning.
Developing The .30 RAR
"While the 6.8 SPC is certainly being used for deer hunting, from a cartridge development standpoint, the 6.8 was not the optimal cartridge to start with," said John Fink, Remington's brand manager of rifle product development.
While substantially shorter, the .450 Bushmaster-based .30 RAR measures up to the .308 quite admirably. We wonder what's next: 7mm RAR, .260 RAR, .243 RAR, or .338 RAR?
After an inventory of strengths brought about by all the recent acquisitions, the Freedom Group found itself in a very unique position with a host of diverse resources.
Under the new umbrella, it had several entities with decades of experience spearheading the development of the AR platform. It also had the exceptional ammunition-making capabilities of Big Green as well as its famed technical research facility in Elizabethtown, Kentucky.
Within a year of its acquisition, Remington launched a camo-clad "black rifle" in .223 called the R-15 VTR. Less than a year later, we were introduced to its heavyweight brother, the R-25 in .308. While many expected those two introductions would be Remington's laurels on which to rest, a joint ammunition and firearms development program to fill the gap between the two rifles was quietly getting underway.
The Remington cartridge-development team went looking for the most potent amalgamation of copper, brass, lead, and powder that could safely and reliably operate in its new R-15 platform from the confines of an AR magazine. Their goal was to propel a .30-caliber projectile at a muzzle velocity of 2,800 fps with a pressure limit of 55,000 psi--the same pressure as the .223. The case of the .450 Bushmaster cartridge became an obvious choice due to its already established ability to feed in the AR platform from modified AR mags, as well as its cavernous case capacity. The .450 Bushmaster, after all, is the shortened offspring of the .284 Winchester, even though the big-bore is held to about 38,500 psi in the AR.
The case was given a 25-degree shoulder behind a 0.305-inch long neck. Overall length was trimmed to 1.530 inches, and the internal capacity of the case ended up right at 44 grains of water.
"We went looking for a bullet weight that did not affect case capacity," said Tim Tanker, Fink's counterpart on the metallic cartridge side. "We felt 125 grains was the place we needed to be to get the energy and velocity."
Coincidentally, the 125-grain .30-caliber bullet was designed to work specifically at these velocities. So with a 24-inch barrel and 38 grains of powder behind a 125-grain bullet to achieve a muzzle velocity of 2,800 fps below a max pressure of 55,000 psi, the ammo engineers had accomplished all of their goals. All that remained was to give it a name: the .30 Remington AR (.30 RAR).
A ballistically interesting cartridge with an appearance reminiscent of a PPC cartridge, Tanker said the .30 RAR settles in between the .30-30 and the .300 Savage, and it actu
ally exceeds Remington's own 125-grain managed-recoil .308 Win. load. In terms of sheer energy, the .30 RAR even exceeds many modern factory .45-70 loads. And while the energy levels of the 125-grain AccuTip BT .30 RAR can't match those of the 165-grain AccuTip BT .308 load, it does follow the .308's flight path within 3.5 inches at 500 yards with a 200-yard zero.
The rim diameter of the .30 RAR was increased from 0.476 inch to 0.492 inch in order to prevent any possibility of it being chambered and fired in a .450 Bushmaster rifle. The increase in head diameter combined with higher operational pressures than the big-bore .450 all but eliminated the ability to use a standard bolt with an enlarged breechface.
A ground-up redesign of the AR upper receiver was mandated. This is where the newly acquired St. Cloud contingent came in. The DPMS boys in Minnesota have been on a mission to build game-getters--from mice to mountain goats--since the company started more than 20 years ago, so they jumped at the chance to make this cartridge work in the R-15 platform. The results were genius, in effect, redesigning a .30-caliber R-25 upper to work on the R-15 lower.
The R-25 bolt-carrier group (top) is substantially larger and heavier than the R-15 .30 RAR unit (middle) and the standard AR-15 group (below).
They started with the bolt. Scrapping the standard AR bolt, they opted for the R-25 bolt, shortening it, reducing its body diameter, and contouring it to operate within the standard R-15 bolt carrier. They developed a dogleg-shaped extractor to follow the contour of the reduced diameter of the body to the full-size bolt head. The plunger-style ejector is slightly beveled and 0.185 inch in diameter, 0.035 inch larger than the standard R-25 ejector.
Because the magazines used are essentially GI mags modified into a single-stack configuration, the bottom two lugs of the bolt are beveled to facilitate feeding.
With a lug-to-lug outside diameter of 0.89 inch, there was no getting around the use of an R-25 barrel extension. A single feedramp is milled at the 6 o'clock position of the barrel extension to facilitate feeding from the 4-round single-stack magazine.
The fluted, 22-inch chrome-moly steel barrel measures 0.98 inch in diameter out to the gas block and steps down to 0.75 inch from the gas block to the muzzle. The target crown is recessed 0.045 inch. The barrel is button rifled with six grooves and a twist rate of 1:10.
The larger barrel extension required a larger upper receiver to accept it. The engineers started with a raw R-25 extrusion of 6066-T6 aluminum. The internal dimensions were machined to match that of the R-15. Externally, the receiver was machined to include a standard forward assist, a brass deflector, and a Picatinny-spec flattop rail. With a width of 1.3 inches, the receiver body is 0.1 inch wider than the standard R-15. A recess is milled in the left side of the receiver to accommodate the upper paddle of the lower's bolt release. To allow room for the larger .30 RAR spent cases, the ejection port is 0.58 inch, compared to the 0.50 opening of the standard R-15.
The gas-port size was optimized at Remington's Elizabethtown R&D facility using high-speed video. Analysis of the video provided proof of the bolt's velocity in order to fine-tune the gas-port size.
Above, the .30 RAR bolt (middle) shares the body of the .223 bolt (left) and the head of the .308 bolt (right); the dogleg extractor is unique. To the left is the same lineup with a .450-class bolt placed second from the left. The .30 RAR's higher operational pressure of up to 55,000 psi required a thicker bolt shroud.
The lower receiver is all R-15. A standard buffer and buffer spring back up the bolt carrier. Inside is the standard single-stage trigger, and below is the standard grip. Pop the upper on the lower, and the R-15 .30 RAR is created.
To The Range>br>I recently jumped on the opportunity to receive the very first R-15 in .30 RAR out of the factory. As soon as I knew the rifle was on its way, I planned a quick trip to South Texas, lined up a one-day pig hunt, and scheduled some time with Dr. Ken Oehler on his range. While I needed to borrow his personal Model 35P, I admit I'll use just about any excuse to hang out with Dr. Oehler.
I topped the rifle with my NightForce NXS 5.5-22X 56mm for accuracy testing and laser bore sighted it. I shipped off some pre-production factory ammo--123-grain Metal Case (MC) and 125-grain Core-Lokt PSP--then I boarded a plane for San Antonio.
At Dr. Oehler's range, the .30 RAR's similarities to a PPC cartridge proved to be more than looks alone. Right out of the gate, the R-15 shot a one-hole, five-shot group with the MC. Average group size was easily under an inch, as indicated in the chart. The Core-Lokt opened up a bit, but it squeaked in at 0.04 under an inch. Average muzzle velocities for 10-round strings from the 22-inch barrel were 2,721 fps for the MC and 2,770 fps for the Core-Lokt, slightly down from the advertised 24-inch-barrel numbers of 2,800 fps. Recoil was negligible, and even at 22X, the crosshairs didn't move much on the paper.
The R-15 .30 RAR upper (right) is machined from the same extrusion as the .308 R-25 (left) to accept the larger barrel extension. Since it uses essentially a single-stack magazine, the R-15 has a single feedramp (red arrow) as compared to the pair of feedramps in the R-25 (yellow arrows).
After accuracy testing, I switched to a new Trijicon 1-4X 24mm AccuPoint scope and sent a slew of rounds downrange to get ready for the next day's pig hunt. All range time totaled, I burned up about 200 rounds with only one failure to fully eject a spent case. I am not sure what caused the malfunction, but I was using prototype magazines in a very dirty rifle when it happened.
The next day, my hunting buddy Hunter Lutto and I headed down to hunt a property managed by my friend, Jeremy Williams of 5J Hunting Ranches. The 2,500-acre ranch was loaded with pigs, but they stayed put, concealed in the brush, until the sun dropped below the horizon. It was then that the wild pigs came teeming out to a deer feeder 180 yards away from where Hunter and I set up. In the melee of feeding, not one of the decent-sized pigs gave us an unobstructed shot without worry of an unintended pass-through hit on a second pi
g. Fifteen minutes into the pig scrum, they trotted off into the bush as quickly as they had shown up.
I thought we were hosed. But at the very edge of dark, Hunter spotted one of the bigger boars as it stepped out of the prairie grass 130 yards out. The black German #4 crosshair disappeared on the side of the black pig, but the glow of the green Trijicon dot clearly marked the spot a bit behind the shoulder. I squeezed off the shot. The solid "THWAP" was superfluous evidence, as I could see the impact wave through the scope at 4X.
In keeping with the lightweight and wieldy theme of the new platform, the author mounted the new Trijicon 1-4X 24mm AccuPoint scope via GG&G's new FLT 30mm forward scope mount with AccuCam Quick Detach base. The Trijicon weighs in at a mere 14.4 ounces and provides a true one-to-four power range, perfect for up-close to mid-range shots. The battery-free illuminated dot fills the intersection of the German #4 crosshair and is powered by both a fiber-optic element and a tritium phosphor lamp. Its design and element coatings provide for a wide angle of view and plenty of resolution, especially during dusk and dawn, the periods when game animals are most active.
Hunter and his 12-year-old eyes get the credit for finding the boar in the tall grass and near-total darkness about 100 yards from where he was hit. I was unable to perform a postmortem because of the dark and a finicky circuit breaker back at the ranch house. But from what I could see and feel, I deduced that the shot went through the barrel-chested boar, pierced both lungs, and came to rest under the skin between two ribs on the off side.
It was enough evidence to give me all the confidence I need to take the R-15 and the .30 Remington AR on my next whitetail hunt this fall. That's perfect timing, as Remington plans to have rifles flowing to dealers beginning in June.
Full production runs of ammunition will also put the three new loads on store shelves at about the same time, but what really excites me is the prospect of reloading the .30 RAR. Tanker mentioned that since the cartridge isn't using any proprietary hybrid powders, he expects the .30 RAR to be of great interest to reloaders. "Dies are already being cut, and data is being constructed," he said. Remington will have reloading components available next year.
Nischalke and his keen-eyed spotter, Hunter Lutto, bagged this nice tusker in the waning moments of their one-day South Texas hunt.