The XM24: Rock River's New Tactical Bolt Action Rifle

Known for its AR rifles, Rock River steps out with the XM24 Tactical bolt action and the risk pays off.

February 06, 2025 By Joseph von Benedikt

Rock River Arms announced its move into the bolt-action rifle world at the 2024 SHOT show. Long a potent force in the AR-15 and AR-10 semiautomatic market, Rock River earned its reputation by building super-accurate rifles and best-value National Match two-stage trigger groups for ARs.

The new XM24 bolt action carries on the accuracy legacy. The .308 Win. version sent to RifleShooter for testing shot absurdly well.

The XM24 is fed by a detachable box magazine. The barrel-to-action interface is basically a Remage-type (a hybrid between a Remington 700 and a Savage 110), so the model has switch-barrel compatibility. Rock River touts it as a mission-ready, tactical-grade tool swappable between .308 Win. and .338 Lapua. Barrel and action are bolted into an MDT ESS chassis.

The advertised weight is 13.2 pounds bare, although when I put the rifle on a scale with the steel magazine installed (more on this magazine in a bit) it weighed 13.5 pounds.

Action Commissioned

In order to be able to accommodate both the .338 Lapua and the .308, the XM24 is mated with a magnum-length action and chassis. (Photo courtesy of Joseph von Benedikt)

Rock River commissioned a proprietary bolt-action receiver by Pacific Tool & Gauge. Fundamentally it’s a Model 700-type action, with customized ejection port, the Remage barrel attachment system I mentioned, and the addition of a bolt-release button on the left side of the receiver and a Sako-type extractor.

The action footprint is pure Remington 700, enabling it to interface with the vast selection of aftermarket Model 700 stocks and triggers on the market. However, the action top is parallel, rather than stepped like the Model 700, and it takes Savage 110 scope bases instead of 700 bases. However, the XM24 comes factory-fitted with a 20 m.o.a. scope rail.

Square-bottomed spiral fluting gives the bolt body a racy look, and an oversize bolt knob provides a sure grasp and extra leverage for easy functioning. Serial number and cartridge compatibility are laser etched into the bolt handle, to help the shooter choose the correct bolt for whatever barrel is currently installed. The bolt shroud and safety positioning and function are pure Model 700. The trigger is the TriggerTech Primary trigger.

A heavy-contour, straight-taper barrel is attached by a barrel nut, and XM24s come with a “crow-foot” wrench for barrel removal and installation. Barrel diameter is robust, measuring 0.94 inch at the muzzle and about 1.2 inches at the breech. Chambering and twist are engraved into the barrel breech and visible through the cutout in the top of the MDT chassis.

Construction

end of barrel and muzzle brake — A nice side-ported brake tames what little recoil the .308 XM24 has, but von Benedikt has a beef with the fact that the back of the brake has a smaller diameter than the barrel. (Photo courtesy of Joseph von Benedikt)

Barrels are made of stainless steel. They’re air-gauged to ensure precision, then cryogenically treated. This treatment, which involves freezing the barrel in liquid nitrogen, relieves stresses within the metal, and Rock River says the process results in more predictable harmonics. Metal finish is matte black nitride. Up front, muzzles are threaded and an aggressive side-ported brake is installed and oriented via crush washers.

Action and barrel are married with an MDT ESS (for Elite Sniper System) chassis. It’s a robust, heavy-duty chassis made of machined aluminum. MDT’s design focus for the ESS was ultimate precision, configurability and modularity. It does not fold, which is actually a good thing with this rifle because it eliminates the hinge and ensures there’s no flex between the action bed and the stock portion of the chassis.

As with most chassis, the ESS is compatible with various AR-type grips, and MDT’s own Elite pistol grip comes on the XM24. It’s a nice rubberized grip with palm swells.

Aft, the buttstock area is skeletonized and features excellent configurability in length of pull, recoil pad positioning and cheek rest height. To adjust, loosen the appropriate four-winged polymer locking nuts and spin the adjustment wheel to attain the desired length of pull or cheekpiece height. You can even slide the rubber buttpad up and down in a vertical dovetail track until it’s positioned perfectly against your shoulder.

MDT builds the ESS to accept AICS-type magazines. To accommodate both the .308 and the .338 Lapua, Rock River chose the ESS that’s set up for long-action magazines. There’s a dual-winged mag release lever positioned at the front of the trigger guard. It’s easily activated with the tip of the trigger finger whether shooting right- or left-handed.

Generous internal beveling on the magazine well helps guide the magazine into place, making the process of seating a freshly loaded mag in a hurry quite easy. Forward of the magazine the chassis forms a sturdy, serrated wall to serve as a barrier stop for shooting from improvised positions. A short section of a composite material is installed there, and this provides a warm-to-the-touch place at the balance point of the rifle to hold and carry it. The machined aluminum fore-end/handguard is octagonal in shape, rich with M-Lok slots, and it has a large cutout in its top to allow the use of big tactical scopes with massive objective housings.

Before heading to the range to wring out the XM24 Tactical, I attached an Atlas bipod to a section of rail M-Lok’d to the bottom of the fore-end tip. Atop the receiver I mounted a terrific 7-35x56 Leupold Mark 5 scope in a one-piece IMS mount.

Range Report

accuracy results chart — (Chart provided by the author)

Scrounging up five different .308 target loads, I was off to the range. It was a balmy spring day but cold enough that the barrel would cool quickly. Because of the massive barrel and the rifle’s intended tactical/precision purpose, I fired three consecutive three-shot groups without allowing the barrel to cool, with each type of ammo. This test protocol enables me to determine whether accuracy degrades or point of impact shifts as the barrel heats. Neither occurred. No surprise there. Owing to the sizable diameter of the barrel I was pretty sure the rifle was going to shoot consistently well.

I first ran a series of groups with Hornady’s Steel Match ammo topped with 155-grain hollowpoint boattail bullets. Even though it’s an older “budget” target load, three consecutive three-shot groups averaged just 0.56 inch. The XM24 was off to a great start.

SIG’s 175-grain OTM load took top honors for the day, posting an average of just 0.40 inch. Next came Hornady’s TAP load with 168-grain A-Max bullets; they stretched the caliper to 0.52 inch.

Four of the five loads tested averaged less than an inch at 100 yards, and three of the five averaged 0.56 inch or less. That’s excellent accuracy and consistency.
Recoil, thanks to the muzzle brake and to the rifle’s massive weight—I estimate it was around 18 pounds with the scope and bipod—was mild. Ergonomics were very good thanks to the outstanding configurability of the chassis.

Am I Triggered?

The feel of the TriggerTech Primary was nice and crisp, and it released at precisely three pounds with less than an ounce of variation, as tested with my Lyman digital trigger gauge.

Any downsides? Yes. For starters, the bolt was a little sticky in operation. I get the sense this is due to the very snug tolerances of the bolt in the raceways. There’s very little play between bolt and action. Even a generous application of fine gun oil didn’t eliminate the slightly sticky feel.

Unfortunately, Rock River sent me the wrong magazine by mistake, one for the .300 Win. Mag. The XM24 in .308/.338 comes with a single-stack MDT that holds 10 rounds in .308 and five in .338 Lapua. Function was 100 percent reliable, though, when rounds were fed through that mag—even if the cartridge-to-follower fit was sloppy. Most of the cartridges I single-loaded into the side of the action fed fine too, but occasionally one would hang up, with the tip caught somewhere around the barrel breech.

However, I don’t think the action has the proper dimensions for the short-action .308 Win. cartridge, and I think the rifle would be better as a .338 Lapua than as the .308 I tested. Also, the 26-inch .308 barrel on the XM24 may have been en vogue with SWAT snipers in the 1990s, but it’s completely out of date on a modern rifle likely to be equipped with a suppressor. Today’s shooters—both civilian and military—are trending to shorter barrels. The weight of the rifle and the length of the action and barrel would have been justifiable with the heavy-kicking .338 Lapua cartridge. To be perfectly candid, I found the XM24 mildly ridiculous when paired with the .308 Win.

Versatile, but Slow

While Rock River touts the ability to change between the two cartridges, it’s not a quick-change barrel system. You’ll need to remove the barreled action from the chassis, and you’ll certainly need a vise to hold the barreled action securely while using the crow-foot wrench to break the barrel nut free.

After changing barrels you’ll also need headspace gauges to set headspacing before torquing the barrel nut back to spec. You’ll need an entirely different bolt assembly for each barrel as well. In other words, it’s not as if you can pop a locking bolt loose, yank one barrel out and snap the other into place during the heat of battle.

Plus, with all due respect, the .308 Win. and .338 Lapua are no longer “…leading long-range cartridges,” as Rock River calls them. I shoot on a weekly basis at a range where competitors in PRS, NRL Hunter and ELR disciplines regularly gather, and none—I repeat, none—of them are using the .308 Win. or the .338 Lapua.

Attaching the name “Tactical” to the XM24 and using descriptive terms such as “mission deployable” may offer the platform some saving grace, as certain specialized branches of the military still do use the .308 Win. and .338 Lapua. However, savvy shooters on the cutting edge of the long-range disciplines are opting for newer, more efficient cartridges.

Pros and Cons

front end of rifle with scope and bipod — M-Lok slots in the fore-end provide plenty of places to add accessories, and the fore-end features a composite insert as well as a serrated barrier stop. (Photo courtesy of Joseph von Benedikt)

Allow me one other gripe. The rear of the muzzle brake is smaller in diameter than the 0.94-inch barrel, leaving the sharp-edged shoulder of the barrel vulnerable to dings. Even a tiny ding can cause a suppressor to spin out of square, risking at worst a baffle strike when the rifle’s fired and at best compromised accuracy. Also, there’s a sizable channel created by the smaller-diameter crush washers between the muzzle brake and the barrel shoulder, which will collect dirt and crud. Neither is acceptable in a $5,275 rifle.

Okay, I’ve whined enough. Let’s look at the really impressive characteristics of the XM24. First, it was not only accurate, but it held its accuracy and point of impact when the barrel got plenty hot.

Also nice: Point of impact at 100 yards was nearly the same across four of the five different types of ammo tested. That speaks to the quality of the barrel and how true it’s mounted to the action, as well as how securely and consistently it’s mated to the chassis.

Here’s another positive thing: Once you’re in shooting position, stability and feel of the XM24 are outstanding. The mass of the rifle tames tremors, and the configurability of the chassis makes it both super comfortable and easy to shoot consistently.

Final Thoughts

Again, if the test rifle were in .338 Lapua I would have a hard time finding a single adverse element to point out. It would make much more sense. And if the .338 Lapua version shoots as well as the .308 barrel does—oh boy!

My advice to Rock River Arms would be to either shelve the .308 Win. version of the XM24, or to make a short-action version properly scaled for and chambered in modern short-action long-range cartridges.

However, the .338 Lapua version may be just the ticket for extreme long-range competitive shooters who want readily available ammo rather than hard-to-source hot-rod cartridges such as the .375 CheyTac or .416 Barrett. In .338 Lapua, the XM24 would be a practical, useful tool.