September 01, 2023
Colt doesn’t often offer bolt-action rifles, so I was somewhat surprised when I first saw the new CBX. It’s branded a Colt bolt-action rifle, which is pretty exciting for fans of the brand. However, the CBX is also a collaboration between reputable rifle and accessory manufacturers.
The last Colt bolt guns were the Colt-Sauer, the Colt Light Rifle and the M2012. The CBX action has DNA from the CZ 600, i.e., they share the same bolt. This is not a CZ 600 variant, however. The Adjustable Core Competition (ACC) chassis is from Modular Driven Technology (MDT). While it would be easy to conclude that the CBX is just another precision rifle in a crowded field, Colt’s willingness to build a bolt-action rifle using something other than the Remington Model 700 footprint has far-reaching implications for most precision rifle enthusiasts.
The Model 700 Curse, Vanquished
What I’m about to say will undoubtedly anger some rifle enthusiasts, and that’s unfortunate. The precision rifle community is besotted with Remington M700 pattern. So many custom actions, chassis and triggers are made to fit this early 1960s design. It’s a convenient curse that keeps on giving. Do not misunderstand me, the Model 700 was innovative for that era. It is a round action featuring a bolt body with two locking lugs that rotate 90 degrees to get into and out of battery. Part of the magic was Remington’s ability to turn a section of thick-walled pipe into a rifle action. It was a modern marvel of efficiency. The secret was its round shape. Manufacturers and gunsmiths alike could spin it on a lathe, which made it easy to cut concentric threads to accept the barrel and grind a square face against which the barrel could shoulder.
The problem with the Model 700 footprint is that its durability is always limited by its round shape. Bolt a Model 700 barreled action into an aluminum chassis, fire up the high-speed camera and watch the thrill-ride that ensues when firing a round. The old gun will buck and snort and rattle around. Bedding the action to the chassis increases the amount of contact it has and reduces a barreled action’s movement, but most Model 700 actions that sit in a chassis never received this treatment.
Making the action from a section of round pipe leaves just a thin-walled section to which two action screws must attach. One screw sits forward of the magazine and the other sits behind the trigger and threads into the action’s tang. Neither screw has much action to thread into, so the shooter must pay attention to ensure the screws don’t come loose. The Model 700 is the reason a couple generations of American riflemen kept a torque wrench close at hand. This action screw arrangement works well enough for a rifle seeing casual use, but it became problematic in the hands of snipers, mountain hunters and competition shooters. If the action became loose, a point of impact shift was almost always guaranteed.
Colt’s CBX action is entirely new and square on the bottom. Where the ubiquitous Model 700 doesn’t have much action screw engagement or receiver mass, the CBX action’s squareness gives it massive steel blocks with plenty of screw engagement. A goal for any rifle action is to have more thread engagement with the receiver than the fastener’s diameter. With the CBX action, the screw measures .19 inch in diameter and has .3-inch of thread engagement. By comparison, a Remington Model 700 receiver only has about .11 inch of thread engagement. There’s just not much material for the screws to grab. Colt addressed this problem.
In addition to getting the action screw issue resolved, the CBX does a much better job of mating with a chassis than the Model 700 footprint. The CBX is flat on the bottom with a massive recoil lug that is .41-inch thick! The front action screw threads into this massive lug, just like the old Winchester Model 54 (but larger). The flat bedding surface and massive lug that serves as a home for the front action screw means this receiver has lots of surface area that is in contact with the chassis. The increased surface area contact patches eliminate the unexplained flyers that can occur when bolting a round Model 700 action into a chassis.
Three is Better than Two
The CBX has an interesting three-lug bolt that only rotates 60 degrees to lock and unlock. There are two rows of lugs to provide prodigious lug engagement with the abutments, but that doesn’t mean it’s called a “six-lug” bolt. While the CBX bolt is the same as the one found in the CZ 600, the CBX bolt lugs lock into lug abutments cut into the receiver. This traditional arrangement differs from the CZ 600 where the lug abutments are in the barrel. While the CZ 600’s receiver might be made from either steel or aluminum, Colt representatives told me that the CBX will always be made of steel.
When unlocked and traversing in the receiver, the CBX places one of the lugs at the six o’clock position where it has massive engagement with cartridges poised for feeding in the magazine. Because of that lower lug orientation, this receiver was designed from the start to work with a double-stack magazine. Where a traditional 10-round single-stack detachable box magazine measures 43/4-inches tall, a double-stack magazine measures 31/2 inches tall. This eliminates more than an inch of clap-trap hanging down from under the rifle while maintaining the same capacity. There’s less to snag when shooting from field positions, which happens more often that you’d think.
There’s also the fact that metal double-stack magazines feed so smoothly and effortlessly that, once experienced, it’s hard to accept anything else. While the CBX was designed to use a double-stack magazine, it ships with a regular five-round AICS single-stack magazine. The magazine that comes with the rifle works just fine, but know that the action is double-stack magazine friendly.
I happened to have an Accuracy International AW magazine handy and used it for testing the CBX. These are more expensive magazines and supply is limited, hence the reason Colt doesn’t ship them with the CBX. The AW magazine worked perfectly — when pushed from the bottom to keep it in close contact with the receiver. This happens because the magazine catch the ACC chassis ships with is a catch meant for use with AICS (i.e., single stack) magazines. If you contact MDT customer service (604-393-0800), you’ll find that they offer a longer AW-friendly magazine catch that positions the double-stack magazine in the right spot. (I would perform this upgrade if I were the owner of a CBX.)
The chassis that comes on Colt’s CBX is the MDT ACC with the most basic buttstock assembly available. That was undoubtedly done to keep the price under $2,000, which was a wise decision. The ACC chassis is one of, if not the most, popular chassis is production. It sees heavy use in the Precision Rifle Series (PRS) and in recreation.
The ACC has a forend that just a hair longer than 17 inches. It’s flat on the bottom and has Arca rail integrated. This allows the shooter to quickly attach and reposition bipods and tripods anywhere along the forend’s length. There are weights available from MDT that ride inside the barrel channel and along the sides that quickly add several pounds to the rifle, if needed. Where the bare chassis weighs just a more than 4 pounds, attaching all the optional weights can increase that number to more than 12 pounds. That may sound crazy, but adding weight reduces felt recoil. Adding weight to key areas allows the rifle to balance on a barricade without tipping over during recoil, too.
The simplified buttstock on the CBX still has an adjustable comb and a spacer-adjustable length of pull. This allows the rifle to be tailored to fit just about any adult. Should you decide that you need a quick-adjust stock, short stock, or folding stock you will find MDT offers one.
One of my favorite features about the CBX is the adjustable trigger. I could get G&A’s sample adjusted down to 1.6 pounds with no detectable creep. As far as factory triggers go, the CBX’s is exceptional. A small Allen wrench was all that was required to tune it.
The bolt offers toolless disassembly, meaning a quick twist of the bolt shroud and the firing pin assembly separates the two. There is even an unlock symbol machined into the bolt body to show us which way to twist. This feature is common on custom actions and makes life easier for routine maintenance, especially in the event of a pierced primer where it might be necessary to dislodge pieces from the firing pin channel inside the bolt body.
At 101/4 pounds (for just the rifle), the CBX isn’t a lightweight. Shooting a .308 Winchester has never been punishing, but G&A’s weighty rifle was a pleasure to shoot. I mostly used the AW magazine and think, with the longer magazine catch from MDT, the CBX and AW magazine were meant for each other.
Accuracy was consistent with fewer flyers than I’d normally expect. I attribute the consistent accuracy (small difference between best group and average group) to the superior action/chassis interface of the CBX receiver.
The CBX will initially be available in 6.5 Creedmoor and .308 Winchester. It is an excellent choice for anyone interested in precision riflery, from casual plinking to two-day matches.
- Type: Bolt action
- Cartridge: .308 Winchester (tested), 6.5 Creedmoor
- Capacity: 5+1 rds.
- Barrel: 24 in., 1:10-in. twist
- Overall Length: 44.9 in.
- Weight: 10 lbs., 4 oz.
- Stock: MDT ACC
- Grip: MDT
- Length of Pull: 12.5 to 14.25 in.; spacer adjustable
- Finish: Matte blued
- Safety: Two-position lever
- Sights: None
- Trigger: Adj.; 2 lbs., 8 oz. to 5 lbs.
- MSRP: $1,899
- Manufacturer: Colt, 800-962-2658, colt.com
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