Christensen Arms MPR Rimfire Rifle: Bughole Spectacular

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Christensen Arms has become well known for its high-end centerfire rifles, which are sought after by hunters and long-range practical shooters. But why should centerfire guys and gals have all the fun? The company recently introduced a Modern Precision Rifle (MPR) Rimfire, and it delivers the goods whether you’re a hunter, competitor or recreational shooter who wants the latest and greatest.

A chassis rifle, the MPR Rimfire is available in .17 HMR, .22 Long Rifle and .22 Mag., and in barrel lengths from 16 to 20 inches. The 18-inch barrel on the .22 LR sample I tested is where a lot of the magic happens.

The liner starts as a solid bar of 416R stainless that is drilled to a .0020-inch tolerance, button rifled and given a match chamber. At this stage it’s heat-treated to relieve internal stresses, followed by precision lapping to produce a flawless bore finish. Finally, the liner is turned down to its final dimensions.

Now here’s where you should know that Christensen, which has its roots in aerospace engineering, is a pioneer in carbon-fiber barrels. It takes that barrel liner and lays up multiple layers of multidirectional carbon fiber to add back the rigidity and strength that’s lost when the liner is turned down to such a thin diameter. The result is a barrel that’s much lighter than an all-steel one and offers superior control of barrel harmonics as well as thermal control.

Harmonics

Granted, heat isn’t such a big deal with a .22 Long Rifle, but harmonics are. A .22 bullet spends a comparatively long period of time in the barrel, and inconsistent barrel oscillations can wreak havoc on accuracy.

Harmonics control doesn’t end with the carbon-fiber process, because the MPR Rimfire’s barrel is also tensioned, which is the final step in the barrel production process.

“Essentially, the 416R stainless barrel is tensioned using a tensioning nut on the muzzle threads against the carbon fiber over-casement that draws the barrel taut and rigid, giving it consistent harmonics,” said Christensen Arms brand ambassador Jeff Bradley. “The barrel tensioning yields a lightweight and accurate barrel in a low pressure application like rimfire calibers.”

The Christensen barrel production method is one reason the company can promise 0.5 m.o.a. accuracy at 50 yards with the MPR Rimfire. More on this later.

Final Touches

The final touches on the barrel include 1/2x28 muzzle threads, and a thread protector is included. When I disassembled the rifle it looked to me like the barrel was a slip or press fit secured with two opposing screws, and that it might be possible to remove the barrel à la a Ruger 10/22—although on such a pricey gun I chickened out on actually trying it. Bradley said in fact it is a slip/press-fit barrel, but he added that the company has no immediate plans to offer component barrels due to headspacing concerns on a user-swappable barrel.

The receiver is machined aluminum and given a black Cerakote finish. A zero m.o.a. optics rail is secured to the receiver with stout Torx screws. The MPR Rimfire uses the same receiver as the company’s Ranger—in fact it’s engraved “Ranger” on the side—and if you’re into the long-range .22 competition or varmint sniping with the .17 or .22 Mag. chamberings, Christensen sells 20, 40 and 60 m.o.a. optics rails.

A flat-style bolt rides within the receiver. This design shaves a surprising amount of weight: The bolt weighs only five ounces. I compared that to the bolts on a CZ 457 competition-style gun and a CZ 452 sporter—both what you would consider “standard” rimfire bolts—and these weigh eight and 8.5 ounces, respectively. So the MPR Rimfire's flat bolt results in a significant weight savings.

The bolt has one other distinguishing characteristic, and that’s the offset extractors. Normally, rimfire bolt extractors are opposite one another at three and nine o’clock. With the bolt facing you, the MPR Rimfire extractors are at two o’clock and about 8:30. Bradley explained this was done to achieve the optimum angle of departure for the spent case.

Stock and Trigger

The trigger is TriggerTech’s Field model, and it’s Remington 700 compatible if you’re someone who likes to change out triggers. While the pull weight on this adjustable trigger was heavier than I would normally want on a rimfire at two pounds, 14 ounces, I didn’t change it. It’s so crisp, and the straight finger lever provides such a great direct-line pull, that I felt like I was breaking good shots right out of the box. So why mess with it?

The safety is a two-position rocker that does not lock the bolt. Feeding is from Ruger’s BX-1 rotary magazine, and one 10-rounder is supplied with the rifle.

The MPR Rimfire’s chassis is everything a competitor, hunter or serious recreational shooter could want. It’s machined from 7075 aluminum billet, and it folds by pressing an unobtrusive button on the left side. It swings with a just-right tension, and when folded it stays put thanks to the company’s Magnelock system. A strong round magnet in the butt locks up against a disk on the right side of the receiver for secure, latchless retention. Just pull firmly on the butt to unfold.

The cheekpiece is adjustable by loosening a pair of 1/8 hex screws and sliding it up or down for a total of one inch of adjustment, and a well-marked scale ensures you can return it to its original position every time. The cheekpiece itself is made of Christensen’s FFT carbon fiber. FFT or Flash Forged Technology produces super-light but strong carbon-fiber components. The cheekpiece is flat on top and angled on the sides.

Options and Adjustability

The length of pull can be changed by loosening an additional set of 1/8 hex screws, and it features two inches of adjustment and another well-marked scale for returning to position if it’s moved. The buttpad is from LimbSaver, and it features a series of ridges that work with the soft material to keep the stock anchored in your shoulder.

Six QD sockets, three on each side, provide a lot of flexibility in adding a sling. A pair of threaded holes in the toe allows you to install a bag rider. Christensen sells the necessary slotted MPR monopod rail ($27–$40) for its adjustable bag rider ($275), but companies like Long Shot Precision (AdjustableBagRider.com) also make aftermarket rail/bag rider setups for the Christensen MPR chassis.

The pistol grip is Magpul’s K model. Featuring a 20-degree grip angle, it’s nothing fancy, just a perfectly serviceable grip. But this is the beauty of chassis guns like the MPR Rimfire that use standard AR-style grips. The world is your oyster in terms of aftermarket options, and they're a snap to install.

The 14-inch handguard—a 10.5-inch length is also available—is made of the same FFT carbon fiber as the cheekpiece, and man is it light. How about just a tad over seven ounces? But again, it’s strong thanks to the company’s FFT technology, so you can feel confident about attaching accessories to its multiple M-Lok slots at three, six and nine o’clock.

Accuracy Results

The handguard is attached to the chassis with eight Torx screws, and you’ll need to remove the handguard if you want to pull the barreled action from the chassis. Should you decide to do this, you’ll find that the action screws have thread-locking compound on them and require a bit of force to break free the first time. The owner’s manual lists the recommended torque values for reassembly.

For testing I mounted my Bushnell Match Pro 6-24x56mm atop the zero m.o.a. rail. With high rings I was just barely able to look squarely through the scope with the comb in its lowest position, so I went with extra high to give me more latitude in comb height. I also added a Warne Skyline Pro bipod for part of the test by installing a short M-Lok rail section on the bottom of the handguard.

Earlier I mentioned that the MPR Rimfire promises 0.5 m.o.a. accuracy at 50 yards, and my test rifle came with a test target—complete with serial number, test date and SK Match ammo noted—with a group measuring a tiny 0.15 inch. I was guessing the test group had been fired from a cradle, and I was doubting my chances of achieving anything that good myself.

Wrong on both counts. I learned that Christensen tests its groups hands-on, not from a cradle. And while it was only a single group, one of my first efforts produced a 0.15-incher with Lapua Super Long Range, along with a 0.20-inch cluster with the same ammo. And those were five-shot groups, as opposed to the three-shot group on the test target.

Different Positions

Take a gander at the 50-yard results in the accompanying chart, which are averages of five five-shot groups. Every single average makes the grade in terms of Christensen Arm’s accuracy guarantee.

The 50-yard testing was from the bench with a Caldwell front rest and Protektor rear rest. For the 100-yard portion, I went prone on a mat with the Skyline Pro bipod and a WieBad rear bag. These results are the averages of three five-shot groups instead of five, and while I wasn’t able to keep that 0.5 m.o.a. accuracy at the farther distance, the groups were still quite good because, hey, 100-yard .22 shooting is hard.

I did test one load at 100 yards with a Silencer Central Banish 22 suppressor, and as you can see it made little difference. While I have found that suppressors can affect accuracy significantly with centerfire rifles, in my experience that hasn’t been the case with rimfires. Still, depending on your load, you might find that a suppressor will change the accuracy profile of the MPR Rimfire.

I didn’t have any barriers to shoot from like you might find at an NRL22 match, but in dry-firing the rifle off some improvised rests at home I found the rifle to be nicely balanced for such work.

Working the Bolt

The trigger is fantastic, and the ability to adjust the length of pull and comb height is key to good practical accuracy. I remember from my old three-position smallbore days that we were constantly making these adjustments because when you go from, say, prone to offhand, your orientation to the rifle changes—so the fit needs to change as well. The MPR Rimfire's chassis gets you there.

My only criticism is how the rifle feels when working the bolt. There were zero issues getting the rifle to chamber a round or eject an empty, but between the lightweight bolt and the rotary magazine it simply didn't feel as smooth as a rimfire with a standard-weight bolt and single-stack magazine. I did check to ensure the cartridges were presented properly to the chamber and not shaving bullet lead, and it was good to go.

The MPR Rimfire really is a do-it-all rimfire. While I don’t have the scratch to drop more than a grand on a plinking rifle, there are people out there who can and will. Weight with the Bushnell in those extra-high steel rings was about 8.25 pounds, which I think is a good weight for practical or long-range competition—where it would excel—or for field-bench varmint sniping.

But if you threw on a smaller scope in ultralight rings, you could conceivably knock off a pound or so to create a great stalking rifle for groundhogs, squirrels and such—folding the stock for easy stowing in a pack. For this pursuit, the platform’s versatility is boosted by the flatter-shooting .17 HMR and .22 Mag. chamberings, and since it takes Ruger rotary magazines, you’re not limited to the 10-rounder that comes with the rifle.

Forward Thinking

Christensen Arms is one of the more forward-thinking outfits in the firearms world, pushing the boundaries of what is possible for sporting rifles. And it seems to me the firm is not about tech for tech’s sake, but rather it comes up with sensible solutions for discriminating shooters and hunters. The MPR Rimfire is a shining example of this, a rifle that brings the cutting edge to all us rimfire fans.

Christensen Arms MPR Rimfire Specs

• Type: bolt-action rimfire
• Caliber: .17 HMR, .22 Long Rifle (tested), .22 Mag.
• Capacity: 10-round BX-1 rotary magazine supplied
• Barrel: 18 in. tensioned carbon fiber w/416R stainless liner; threaded 1/2x28, thread protector supplied
• Length: 35.5–37.5 in
• Weight: 6.2 lb.
• Construction: machined Burnt Bronze Cerakote aluminum chassis w/Magnelock folding butt, adjustable comb and length of pull; FFT carbon fiber handguard w/M-Lok slots
• Trigger: TriggerTech adjustable single-stage; 2 lb., 14 oz. pull (measured, as received)
• Sights: none; 0 m.o.a. optics rail
• Safety: 2-position non-bolt-locking rocker
• MSRP: $1,250
• Manufacturer: Christensen Arms, ChristensenArms.com

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