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Cobb .50 cal - New Improvements on an Old Design Print
Product Reviews
Written by Rob Sheppard   

Cobb .50 cal;

New Improvements on an Old Design

by Rob Sheppard
Copyright 2004 Sniper's Paradise

One of the ways to gain quick recognition of a new product is to take something that everyone wants but offer it in a package no one else has. Cobb Manufacturing Inc. has done that with their new Fast Action .50BMG, or FA50 for short.The new twist on the standard .50BMG theme here is in the action, or, as CMI calls it, the Fast Action.

They looked at the strengths and weaknesses of the 2 basic .50BMg actions, the bolt action and the semi-auto, and came up with something new. They wanted a rifle with the accuracy of a bolt-action, but quicker to operate. The semi-auto .50’s tend to be less than desirable in the accuracy department. One of the main drawbacks of the bolt action variants is that you have to move your head off of the stock to cycle the bolt. CMI also wanted to deal with the capacity issue that many models have.

The Fast Action is built on an AR15 style platform with a separate upper and lower receiver fastened with 2 pins, fore and aft. The upper and lower receivers are machined out of T7-7075 aircraft aluminum with an integral MIL-STD 1913 rail. There is no charging handle protruding from the rear of the receiver, ala AR15. Instead, there is a charging handle projecting from the left side of the receiver, similar in placement to an FN FAL. The handle is “fixed” in that it does not fold down like some FAL variants. The reason for this is so that it can be used as a “forward assist”. Unlike the Barrett M82A1, the FA50 was designed so that it will not fire if the weapon is out of battery. The buttstock is a standard A2 buttstock, along with the pistol grip, allowing the use of any aftermarket stock or pistol grip.
The bolt is machined out of 4340 steel and the bolt carrier is machined out of 4150 steel. The bolt head is the spitting image of an AR15 bolt, just much larger, with a very beefy extractor. All steel parts are protected with a parkerized finish and the aluminum bits are MIL-SPEC black hard anodized. Custom Duracoat finishes are also offered in a variety of colors and camouflage patterns. Duracoat finish of the rifle is $375 with the scope and rings done for an additional $125.

The barrel on the standard rifle is a 30”, free-floated Lothar Walther with a 1 in 15” twist. They also offer a carbine with a 22” barrel. Capping the muzzle is the excellent Armalite muzzle brake. CMI is currently working on the design of their own propriety muzzle brake which they claim will be an improvement over the Armalite. With the 30” barrel the rifle weighs 29 pounds and has a length of 58 inches. The carbine is 50” long and weighs 26 pounds.

Rounding out the package is a steel M60 bipod, 2 10-round staggered column box magazines and a MIL-SPEC padded sling available in black, woodland camo and desert camo, all packaged in a fitted Starlight case.

Options, other than the custom finish, include additional 10 rounds magazines for $75 a piece and an extended 28.5” MIL-STD 1913 detachable rail for $250. The rail extends over the handguard for additional mounting options.

CMI manufactures the magazines themselves and they were beauts. Very sturdy, with machines aluminum followers, they functioned perfectly. They hold 10 rounds in a staggered configuration and resemble M14 magazines cut for an AR15 magazine release.

The following FA50 parts will interchange with MIL SPEC AR15 parts: trigger and trigger spring, safety selector switch, detent and spring, trigger and hammer pins, pistol grip and screw, buttstock assembly, trigger guard and pin, buffer detent and spring, magazine catch and spring, and lower receiver extension tube.

The FA50 was easy to operate. Load one of the 10 round staggered column magazines and insert it straight into the magazine well, exactly like an AR15. Pull the bolt fully to the rear and let it fly. The bolt has a large buffer-like spring to the rear that shoves the bolt forward, stripping a round from the mag and chambering it. Give the handle a shove to ensure that the bolt is fully seated and you are ready. Personally, I rarely gave the bolt the extra little shove and it never failed to seat for me. Each time you fire, pull the bolt to the rear and let it go. It was quick, simple to operate and functioned flawlessly. I never had to lose my stock weld to chamber a new round and the charging handle was easy to reach. A little note, if you are using rings like the Badger Max 50’s on the test model I fired, with large nuts to hold them to the mount, you’re better off mounting the nuts on the right side of the optics. That will save you from skinning your knuckles. Ask me how I know!

Recently, myself and fellow Sniper’s Paradise Staff member John Schulze had a chance to test this new system. We were supplied with one action, 2 barreled upper receivers, and a Leupold M1 16X mounted in Badger Ordnance Max-50 rings for testing. The supplied ammunition was pulled and reloaded M33 ball loaded by Arizona Arms with a moly-coating. While we didn’t have a chronograph to measure velocity with, standard M33 ball ammo is a 661 grain projectile doing around 2910 fps out of an M2. The FA50 will handle any standard .50BMG ammunition.
The first upper receiver had the standard 30” barrel with a Sound Tech M2 Sound Suppressor. The M2 suppressor weighs 5.5 pounds, a noise reduction of 30db and attaches with left-handed threads and a quick locking collar. Suggested retail of the suppressor is $1200 plus the one time NFA tax of $200.
The second upper receiver was the 22” carbine with the Armalite muzzle break. The carbine upper drops the weight to 26 pounds.

We were only able to test the system on a 100 yard range. The temperature was around 94 degrees F (an average Georgia day!). We shot off of the supplied bipod with a rear bag, both from a bench and prone.

We shot the suppressed rifle upper first. I had never seen, let alone shot, a suppressed .50 before. It was quite revealing. The noise level was such that it was very comfortable to shoot wearing foam ear plugs only, say on par with a .308, but deeper and without the sharp crack. Because the muzzle is about 4 feet in front of your head it sounds even quieter while shooting it. The suppressed version has more recoil than the compensated model, but was still very easy to shoot. The recoil was about on par with a 12 gauge shotgun using field loads, not even close to a 12 gauge with slugs. I fired in the neighborhood of 50 rounds out of the suppressed version and felt that I could continue to do so all day. Even prone it was easy to shoot. I have shot numerous bolt actions in various .30 caliber magnum calibers that had more felt recoil. In addition, there was none of the muzzle blast commonly associated with .50BMG’s.

The trigger pull was very crisp, but also very heavy. According to CMI, that’s the nature of the beast. If they lighten the trigger down too much it will not reliably ignite the primers. The crispness helped and overall the trigger was easy to use once you got used to it. I would very much like to see a lighter trigger, but it was no worse than other .50’s I have shot. It required a little more aggession than I commonly use on a precision rifle.

The charging handle required a stiff pull but was easy and quick to operate once you had a feel for it. We experienced no problems whatsoever with functioning. I envisioned a well-trained 2 man team, one firing while the other worked the bolt. Even without that, you could work the bolt and reacquire the target about as fast as you could accurately shoot.

My best group was well under the guaranteed 1 MOA, more like .5 MOA. I shot several other groups that were just at and under 1 MOA. This was shot with approximately 5 minutes between each round and the bolt locked back to help cool the barrel. In the attached photo the group in the orange is my best 3 shot group, with the one underneath it a separately fired 3 shot group, just around .75 MOA. I can’t wait to take the system out and put some distance on it, as that is where the big .50’s really excel.

With the temperature as high as it was, and as many rounds as I was sending down range, the mirage became so bad off of the barrel/suppressors that I had to stop for a cool down period to let it dissipate. CMI stated that they are looking at alternate materials for manufacture of the forearm which would greatly lessen this effect.

We replaced the suppressed upper with the 22” compensated carbine upper and continued to shoot. I had never fired a .50 with as short a barrel before. The recoil was negligible due to the Armalite muzzle break. Also due to the Armalite muzzle brake, the muzzle blast was a bit abrupt. It was like a brisk slap in the face accompanied by a jab in the nose. Nothing to stop us from firing it many times, but it did take a bit of getting used to. Again, this is the nature of the beast. Any .50 with a barrel that short is going to slap you around. Soon I hope to test the compensated rifle upper and see what a difference with extra 8” inches of barrel makes in moving that compensator away from your face. I have shot the Armalite AR50 with this same brake and a 31” barrel. The muzzle blast was a lot less noticeable than with this carbine length barrel and the rifle version FA50 should be similar. More on that in a later test.

I was continually comparing this system to the Barrett M82A1, as that is the .50 with which I have the most experience with. It is what we used in the Marine Corps and I have shot them numerous times since my EAS. I felt the FA50 was superior to the M82A1 in many ways. Quite frankly, I always found the Barrett to be wanting in the accuracy department. The FA50 was more accurate and that is the most important aspect of such a rifle. There are less moving parts which should make it less susceptible to malfunctions under extreme conditions. I also like the fact that the FA50 will not fire if it is not completely in battery. It quickly and easily breaks down for cleaning and transport, simpler and faster than the Barrett.

Overall this is quite some package. Without the suppressor it would balance very nicely and be very portable. The 5.5 pound suppressor makes it quite a bit muzzle heavy. Pull 2 pins and the weapon breaks down into 2 halves for easy storage in the supplied Starlight case. All the machine work was flawless and quite beautiful to behold if you enjoy a well-made piece of steel or aluminum. The entire system was very sturdy and rugged, built to last.

The suggested retail price for the standard rifle is $6995 plus shipping. This compares favorably with the Barrett M82A1 with a suggested retail of $7300. In addition, C3 Sports is advertising the standard 30” rifle for $5600.

Check them out at
or call them at (678)363-5899.

Check CMI’s website at
or give them a call at (770)505-3080.