It doesn’t seem like it was that long ago that just mentioning the concept of a self-loading precision rifle would set many to gnashing their teeth. In the not too distant past, many believed it to be carved in stone that a precision rifle needed to be a drop floorplate bolt-action .308 Win. weighing 17 pounds and topped with a fixed 10X scope. To believe otherwise was to be branded a heretic.
Today’s perception of what constitutes a tactical precision rifle has changed dramatically—and for the better. This adjustment in thinking, based upon actual end-user feedback by troops engaged in battle in the desert, unshackled designers and provided some badly needed creative freedom. NEMO’s semiautomatic Omen is an interesting example of this. It’s not just a “gas gun” but rather NEMO’s take on what a modern self-loading precision rifle chambered for the classic .300 Win. Mag. should look like.
While there has been a big jump in the number of factory semiauto precision rifles, most still chamber standard military rifle cartridges—typically 5.56×45 or 7.62×51. While capable of surprising accuracy, both of these cartridges are limited by their lackluster exterior ballistics and terminal performance.
There are times after all when a job calls for a 22-pound sledge rather than a four-pound hammer. This may be busting tough game at long range, smacking steel way out there or for professional use against targets that shoot back. NEMO’s Omen is intended to provide serious rifleman with a noticeable step up in performance over the .308/7.62.
A relatively new face, New Evolution Military Ordnance (NEMO) was founded in 2011 and is located in Kalispel, Montana. The company was co-founded by U.S. Army Maj. Gen. (Ret.) Paul Vallely, Clint Walker and Kirk Leopold.
NEMO caught the attention of some when it acquired firearms manufacturer SI Defense and partnered with Sonju Industrial. This acquisition and partnership have allowed the firm to acquire aerospace manufacturing expertise. Others took note when NEMO developed its own .308 AR-10 and 5.56 AR-15 platforms. Then, to demonstrate technical expertise, it built an AR-10 rifle out of titanium—an attention-getting project gun.
What makes the Omen so exciting is its .300 Win. Mag. chambering, which celebrates its 50th birthday this year. Introduced by Winchester Repeating Arms Company in 1963, it was preceded by the .264 Win. Mag., .338 Win. Mag. and .458 Win. Mag.—all of which were unveiled in 1958 and based on a modified .375 H&H case. The parent case was blown out and shortened to 2.500 inches, which is significant because it allowed the cartridges to function through standard-length rifle actions.
When the company finally introduced its .30 caliber magnum cartridge, it didn’t simply neck down its .338 Win. Mag. Instead, designers tweaked the case by moving the shoulder forward 0.156 inch, increasing case capacity. The result of their work was a large belted magnum with a case length of 2.62 inches. Rim diameter is .532 inch; base diameter is .513 inch. Shoulder diameter is 0.489 inch, and overall cartridge length is 3.34 inches. Maximum SAAMI recommended pressure is 64,000 psi.
Since its introduction the .300 Win. Mag. has gone on to become the most popular of all the .30 caliber magnum cartridges by a large margin for both sporting and tactical use. It offers a useful step up in terminal performance over standard hunting cartridges such as the .30-06, and long-range shooters appreciate both its exterior ballistics and match-winning accuracy at 1,000 yards (and beyond—thanks to recent developments in projectiles and powder for U.S. government use that have extended its reach well beyond 1,200 yards).
Last but not least, loaded ammunition and components are widely available and relatively affordable compared to many other magnum cartridges.
However, the .300 Win. Mag. is not without its faults. When designers moved the shoulder forward, they created a very short neck—one that’s actually shorter than the caliber of the bullet loaded into it. Many have criticized this feature, claiming a short neck would not hold a bullet in proper alignment with the axis of the bore.
Others have criticized it by saying it provided insufficient tension on the projectile to retain it adequately. This issue is said to be exacerbated when heavier bullets need to be seated deeply to maintain its .30-06-like 3.34-inch overall length.
Then there is the belt, a holdover from the British cartridge on which it is based. On a long, tapered case intended for dangerous game hunting in 1912, the belt made sense. On the comparatively straight-wall .300 Win. Mag. in the 21st century it is nothing more than a nuisance. Although the .300 Win. Mag. is designed to headspace on the belt, few reloaders actually do this because belt thickness varies from manufacturer to manufacturer. More consistent accuracy can be achieved by headspacing off the shoulder. Reloaders can accomplish this by simply backing off their resizing die a quarter to a half turn; this should also extend case life.
It must also be understood that the big Win. Mag.’s performance does come at a price. Hand in hand with stiff recoil is throat-eroding performance. Do not expect to stuff copious quantities of slow-burning powder down a .30 caliber hole and have Methuselah-like barrel life. If you demand performance, peak barrel life may only be 1,200 to 1,800 rounds. But it will be a heck of a ride for those 1,200 to 1,800 rounds.
Like I said, the chambering is what makes the new Omen so fascinating, but the rifle itself is interesting as well. In simplest terms, the new Omen is a variant of Stoner’s AR-10, which utilizes the traditional Rossignol gas tube and a carrier-controlled multi-lugged rotating bolt. It has, of course been scaled up for the larger cartridge.
The Omen is built using a billet aluminum upper receiver. Mated to this is a match-grade 416 stainless steel barrel with a nitride finish and a nickel boron-plated barrel extension. To reduce weight and improve handling, the barrel is 22 inches long and sports a SASS barrel taper to the gas block and runs 0.870 inch forward of the block. The barrel is fluted to reduce weight as well, and it employs a 1:10 twist that allows a wide variety of bullet weights to be used.
My review rifle also wore NEMO’s new A-10 muzzle brake. This design features five baffles and, according to testing performed by Texas University, reduces recoil by a signifcant margin compared to a standard flash suppressor.
<h2></h2>The Omen is essentially an AR-10 with the receiver machined from billet aluminum; the author’s sample was finished in Cerakote in what the company calls its Yeti pattern.
A low-profile gas block is fitted to the barrel and retained by two set screws. The block tucks neatly inside NEMO’s free-floating fore-end system. The fore-end is designed to tie into the receiver to make it as secure as possible. Six bolts clamp the rail to the barrel nut, and two more lock it to the upper receiver.
Rather than being covered in MIL STD 1913 rails it features a single full-length rail at 12 o’clock. If you want more, the fore-end has threaded mounting points that permit the shooter to mount additional short rail sections. This reduces both the weight and diameter of the fore-end, making it lighter and more comfortable in the hand. I found the fore-end fit my hand very well and made it comfortable to carry and shoot from field positions.
Stuffed inside the upper receiver is a nickel boron-coated bolt carrier assembly. The first thing you will notice is the carrier has been redesigned to accept a charging handle. This protrudes from the right side of the receiver, which is slotted accordingly.
The takedown pin was very tight on my sample, and I resorted to a Delrin punch to knock it out. In order to remove the bolt carrier you must first pop the charging handle out of it. I accomplished this with a quick tug.
A spring-loaded buffer mechanism is pinned to the tail of the carrier, and the gas key is firmly staked in place. Removing the firing pin retaining pin took a bit of force, and it’s a bit of a chore removing the firing pin due to its length (4.75 inches) and proximity to the added buffer in the rear of the carrier. A spring has been added to the firing pin to prevent slam-fires. Instead of a standard cam pin, the Omen has one that incorporates a roller bearing.
You can see in the photos that NEMO has deleted the ejection port dust cover and did not bother with the A2-style case deflector. The lower receiver is machined from a billet, like the upper. Inside I found a Geissele SSA-Enhanced trigger. The controls are all straight AR with nothing out of the ordinary added.
Feed is from a large, ribbed polymer magazine. A double-stack dual feed design, it holds 14 rounds. Due to its sheer size, the design appeared fairly robust, and it was fitted with a fairly heavy spring.
While different stock options are available my review rifle came with a carbine-length receiver extension fitted with a Magpul STR collapsible stock. A Hogue Overmolded pistol grip completes the lower.
With the stock collapsed the Omen measured 42.2 inches, and without optics or bipod it weighed 10.9 pounds. My review rifle sported an eye-catching Cerakote finish in what NEMO refers to as its Yeti pattern. Base price on the Omen is a hefty $5,900 while the price tag on it as reviewed is $6,400.
To test the Omen I selected IOR Valdada’s new 1-10×26 Eliminator-LTS—a scope that, thanks to its magnification range, can handle shots from a few feet to more than 1,000 yards. Built on a straight 35mm tube with a 26mm objective lens, it has an overall length of just 11 inches and weighs 25 ounces. Adjustments are in 0.1 mil increments, and each full turret revolution dials in five mils with a total adjustment range of 35 mils.
An 11-position rheostat controls the intensity of the illuminated MP-8 Xtreme-X1 reticle, which features 0.5 and one mil marks, along with finer 0.25 mil marks at the edges to aid rangefinding (although I should point out the reticle is located in the second focal plane, so rangefinding is power-dependent). The bottom vertical stadia features 14 mils of compensation for holdovers. This stadia also features short horizontal stadia for wind/lead corrections that grow progressively longer, Christmas-tree style. The center of the reticle is a dot.
With the IOR mounted in Valdada’s one-piece base, I gathered together seven loads and got to work. Loads consisted of factory hunting and match loads, as well as two handloads and one military rifle team load.
After zeroing, I proceeded to shoot four five-shot groups with each load from the bench at 100 yards. I immediately noticed two things: Recoil is extremely mild, and the Geissele trigger is very nice. The rifle’s low recoil comes courtesy of the self-loading design, the rifle’s overall weight, the muzzle brake and inline stock design, and I would compare the experience to shooting a 7.62×39. This makes the Omen very comfortable to shoot from a variety of positions. More importantly it allows you to get back on the scope quickly, speeding follow-up shots.
Accuracy from the bench ranged from hunting grade to pretty darn good depending upon the load. Best accuracy was obtained using a match load Black Hills Ammunition produced for a military rifle team. This featured a 190-grain Sierra MatchKing at 2,919 fps. My best group of the day was 10 rounds into 0.7 inch at 100 yards. It averaged 0.9 inch for four five-shot groups. A handload supplied by NEMO topped with a 208-grain Hornady A-MAX averaged 1.1 inches at a sedate 2,587 fps.
The one issue I ran into was how quickly the barrel heats. Every time you touch the trigger you are burning a healthy dose of powder, so the barrel heats very fast. Test conditions were a humid 90 degrees, which didn’t help matters much either.
With a baseline for how the Omen shot, I next moved to my shooting tower. Here I engaged reduced and full-size silhouettes prone from the bipod as well as prone, sitting and kneeling. These were placed at random distances from 220 to 530 yards. Here I noted magazines inserted easily, rounds chambered smoothly, and empties ejected cleanly between 1 and 2 o’clock. During these drills the Omen provided rapid hits, and I appreciated its flat trajectory. As noted earlier, the gun was very easy to control—allowing for rapid follow-up shots.
With the light rapidly fading, I moved to shooting prone at 800 yards. This was as far as I was able to work the Omen. Using the Black Hills 190-grain load I fired two five-shot groups. The first put four rounds into six inches, with a flier bringing it out to 11 inches total. My second group put five rounds into nine inches. So my average for this load at 800 yards was 10 inches.
My thoughts? I found the Omen to be great fun to shoot. It was nicely made, and reliability was 100 percent. It’s a very soft-shooting rifle, but as I mentioned, the barrel heats very quickly. Rattle off one 14-round magazine and it’s hotter than a Maxim gun on the Somme in July of 1916. If used energetically, I doubt barrel life would be exceedingly long.
Most of the brass came out of the gun fine, but a couple loads showed ejector swipes. But I encountered no ejection issues, and the Omen chugged through a variety of loads without incident. I rather like the beast. It is great fun to shoot, hits with authority and looks impressive. If you can get past the sticker shock, it is a .300 Win. Mag. to consider.