Gun Test: Ambush Firearms .300 Blackout

Guns and Gear | Contributor

By John Connor, GUNS Magazine

I didn’t know quite what to expect when I opened the box, for two reasons: First, I had no experience with, and was only vaguely aware of the existence of Ambush Arms. I sure didn’t know they are the sporting arms division of Daniel Defense. That would have at least rung some bells for me. I didn’t know much about the .300 Blackout cartridge, either. Basically, I knew it’s a .223 case with a .30-caliber slug stuck in it, a couple of AKA’s, and it had become pretty popular with hunters, particularly feral hog-poppers.

Second, I decided not to do any research on the rifle before it arrived—particularly any reviews online—so my impressions would at least be fresh, unbiased and mine alone. It helped I was crazy-busy with other assignments. And lazy. It didn’t take much of a nudge for it to slip right off my Teflon-coated mind.

Yeah, there was another factor too. I’m not much on “sporting arms,” unless you count combat as a sport. So, I was semi-prepared to be anything from bored to amused… maybe appreciative. But not prepared for this: “Pretty” isn’t a word I would ordinarily use to describe firearms, but—this is one handsome rifle! Nice, clean lines, an uncluttered look of what you might call “intrinsic efficiency,” like a Los Angeles-class submarine. It looks graceful, and in the curves and planes of the stock and fore-end, kinda elegant. You may see it differently but remember, I’m more accustomed to working with firearms which resemble scrap iron mashed into sections of stovepipe, y’know?

There are no colors other than black, discreet white markings and Realtree camo; no gold-plated trigger or contrasting controls, but it’s just right—like the difference between a dude in a hand-tailored charcoal suit vs. some doofus in a cheap rented tux with a purple brocade cummerbund. It ain’t gaudy, just stylish. Gotta admit, the Realtree looks classier than my rattle-can spray paint jobs done with weeds and dead leaves strewn over an innocent black rifle—and it resists wear a heck of a lot better too.

Yup. She’s a looker. But, the prettiest girl at the barn dance can turn out to be an evil-tempered, slew-footed klutz with whom attempting a simple twirl can be a catastrophic evening-ender involving sawdust in your hair, a bloody nose and two broken toes.

That concern was put to rest as soon as I picked her up, put her to my shoulder and swung her around. Insert the word “sweet” here and that says it all. Of course, you can’t be sure with this kind of rifle until you’ve got an optic and a loaded magazine on board, but you can sure get a good clue. I did. My immediate impression was of agility, like fluidly tracking a fast target through heavy brush. Call that “bacon on my mind.”


The fore-end is designed for the hunter and is comfortable in the hand. The bottom rail proved perfect for a Harris Bi-Pod, something John added for the shooting portion of the test.


The generous pistol grip is better suited to hunting than the common AR grip. The grip is hollow and capped should you desire to store some small items inside.


The Ambush Arms .300 AAC comes factory threaded for a suppressor should you decide to add one down the line. More and more states are allowing the use of suppressors when hunting.

They didn’t just slap parts together. It’s not an assembly of components; it’s a thoughtful melding of attributes to create a well-balanced, smooth-swinging, naturally-pointing entity. Kudos to the design crew, Ambush! Before taking the top-down tour, some generalities:

The .300 Blackout, also known as .300 AAC (for Advanced Armament Corporation) and an interchangeable fraternal twin to the .300 Whisper, is essentially a .223 cut down and blown out to 7.62x35mm. It was designed to accommodate both supersonic loads in the 110- to 120-grain range and subsonic loads to 200 grains for sound-suppressed use, doing all this within the AR-15/M4/M16 structure, including use of .223/5.56x45mm magazines. The only significant difference is the barrel and the size of its gas port.

As you can guess from the photos, the heart and guts of the Ambush .300 is a classic direct gas impingement AR-15. It’s a carbine-length system with a low-profile gas block. All the usual controls and features—safety, bolt hold-open and release, magazine release et-inclusive-cetera are in all the old familiar places. Although the Ambush .300 shoots 7.62x35mm rounds, it remains completely compatible with the standard M4 bolt and carrier group. Field stripping, cleaning and maintenance are all samey-same, which for many of you means you can do it on autopilot. That hole in the barrel may be a little bigger than you’re used to, otherwise, it’s all about proprietary features and qualities.


All the controls familiar to AR users are located in their usual spots. The illumination control for the scope is located on the left side of the turret manifold.


Leupold’s new Mark 4 MR/T 1.5-5x20mm illuminated scope tuned for .300 Blackout has a reticle designed for use with either super-sonic or subsonic loads with twin holdover hashmarks in the reticle.

Top Down & Inside Out

The 16-inch barrel is cold hammer forged (as all barrels should be), a process that aligns steel at the molecular level, enhancing accuracy and long barrel life. Then a salt-bath nitride treatment is applied for maximum corrosion and abrasion resistance. Both the barrel and mil-spec bolt carrier group are magnetic particle tested for voids, defects, and the tiniest irregularities. On to the tour!

Topside you’ve got a whopping 15 level inches of T-marked Picatinny “rail estate” for mounting optics, lasers, hydraulic clam diggers etc., plus three more 3-inch modular movable/removable rails at 3, 6 and 9 o’clock on the fore-end. That distinctive fore-end is a free-floated, 12-inch ventilated aluminum tube sporting an Ambush Arms exclusive “shotgun-inspired” hand grip. I gotta tell you, it feels even better than it looks, and is extremely comfortable and solid in the hand. The barrel is an S2W profile, about 0.735 inches in diameter, tipped with a knurled muzzle cap to protect the 5/8×24-inch threads, provided for mounting a sound or flash suppressor.

The charging handle is a BCM (Bravo Company Manufacturing) extended type, medium-latch length. This allows you an easier grasp when working around the rear of an optic. I like the Bravo Company charging handles because they direct force away from the pivot pin, so you won’t shear it when riding the handle hard or “blading” it with the knife edge of your hand, as I do. The upper and lower receivers are mil-spec forged 7075 aluminum, precisely mated, and within lurks a real treat.

The firing group is the premium Geissele SSA Super Semi-Automatic trigger, a 2-stage delight. Total pull weight is 4.5 pounds—2.5 on the first stage and 2 pounds on the second, with a crisp, clean break. It is ideal for combining precision with speed. I have one on a 7.62×51 semi-auto rifle set up for long-range “selective targeting” and love it. If you’re accustomed to single-stage triggers, it just takes a bit of practice to wring maximum performance out of the SSA, with the first stage letting you know you’re on the trigger and the second stage providing match-grade controllability. You can get the precision of double set triggers out of it, but faster and safer.

Ordinary polymer pistol grips and buttstocks on AR’s don’t merit a heck of a lot of attention, but these do. Like the shotgun-inspired fore-end, they are Daniel Defense exclusives. See the textured areas? Those are soft, tactile, comfortable and slightly compressible rubber overmoldings. On the fully adjustable stock, the overmolding provides an excellent cheekweld without any of the slip ’n’ slide effect you get with smooth polymer, especially when you’re sweating. The inboard cant of the rubber buttpad and turned-in toe ease shouldering of the rifle, and there’s a QD mount for a sling.

The pistol grip’s overmolding is well placed too, and the grip also features a dished thumb relief and a middle finger groove. The grip buttcap is a friction and rubber-compression fit, providing access to the hollow interior. Just be sure you don’t put any rattle-prone items inside and you’re good to go. Keep your “emergency Skittles” in your pocket.

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The magazine well is nicely beveled for slick reloading, but there is no electrically-driven Hoover system to vacuum-suck mags into the weapon. Hmph.

Leupold graciously sent us a pristine Mark 4 MR/T 1.5-5x20mm illuminated scope tuned for .300 Blackout, along with their slick, solid Mark 2 IMS integral mounting system with 30mm rings. All that remained was to attach a Harris Ultralight Bipod and then—find a hole in the weather and hit the range…

Good for you, not-so-good for me. This was a short turn-around assignment with a drop-dead deadline, and Mr. Weather was not our friend. It was late January, and as the East Coast braced for “Snowmageddon,” Texas was gettin’ raked by nasty sleet and freezing rainstorms rollin’ in like freight trains. My range had been closed due to slick, frozen mud and ice on the flats. There was supposed to be an 8-hour window between storms—there wasn’t, quite—and I jumped it.

I had the range to myself, except for two guys down in the full-auto bay firing long bursts from select-fire weapons and screaming “Yee-haww!” I don’t think they were shooting for accuracy though. I had to. The sky was solid aluminum overhead, creating twilight effect. Temps were above freezing, but penetrating winds of 25 miles per hour with gusts to 45 were blowing from 2 to 3 o’clock. How bad were the gusts? I secured small items, but one gust scooped the empty rifle case off a concrete shooting table and hurled it several yards down the firing line. I didn’t try to grab it, because when I turned I saw my expensive (for me) spotting scope raise two legs up off the table, balancing precariously on the third leg of the tripod. Already hearing that Crash! Tinkle-tinkle! sound in my head, I grabbed it instead. I put it in the Jeep. So, no benefit of spotting scope. Sorry, no chronograph workup either. I knew better than to even try to set it up without mooring hawsers and twin bollards. The wind had had its way with my chrono before, and it was ugly.

The angle of the wind was perfect for ripping targets off the frames too. After watching four fired-on targets take off for Nacogdoches, or maybe Texarkana, I started taping the right edges of the targets as well as tripling their weight with 10mm staples. The only good thing going for me was, the crests of the high berms weren’t crusted over, and every time a big gust hit ’em, they would toss up heavier dust, bits of vegetation and plastic grocery bags probably coming from downtown Phoenix. So I’d take note of the berm to my right, and try to shoot between Godzilla-gusts. Then a thought struck me. (Some grit too, but a thought.)

You’ve taken time off work, laid out hefty bucks for a pig-busting trip, driven 382 miles, were delayed by two flats outside of Festered Corners, you have one day to git ’er done—and you shoot in the weather you’re dealt. It ain’t always sunny, still and clear. It’s one thing to determine what a rifle will do from a clean bench under fair skies, and quite another thing when Mother Nature is irked. But if you can hunker down with this rifle on a bipod, what can she do? So, maybe poor conditions for me, but good real-world data for you, huh?


I shot eight, 5-round groups with each of three types of supersonic ammo at 100 yards. I knew there would be some throw-aways, and would hope for the best with four groups of each selected “for record.” The sky kept darkening with purple-bellied clouds, so I got to test the illumination on the scope in failing light without violating the “no shooting after the sun hits the horizon” rule. The sun was nowhere to be seen, but the clock said it wasn’t “sunset” yet.

The Ambush .300 worked great. I didn’t get to do much snap-shooting, but yes, the rifle handled, balanced, poked and pointed very, very well. I can’t say enough about the quality of that Geissele trigger, and all the fine points I had listed before—the cheekweld, the grip et al—translated from the shop to the field.


Best actor in a supporting role—literally—was the Harris Ultralight bipod. They are a top choice for fieldwork being tough, super light and fully adjustable.


All standard 5.56 magazines should work, but varying contours of followers will stabilize the .300 Blackout round more or less well (above). Twenty-round polymer MagPul P-Mags and Brownells aluminum magazines both worked fine. The .300 Blackout ammo tested in the Ambush
Arms included (below from left to right) Barnes 120-grain VOR-TX, HPR 110-grain TAC-TX, and G2 Research’s 110-grain Rip-Out. At far right, a standard 55-grain 5.56×45 round for comparison.


.300 Blackout Factory Ammo Performance

Load Best Group Largest Average
(brand, bullet weight, type) (inches) (inches) (inches)
Barnes 120 VOR-TX 1.75 2.125 1.93
G2 Research 110 Rip-Out JHP 1.625 2.5 2.09
HPR 110 TAC-TX 1.625 2.375 2.03

Note: Groups the product of 5-round groups at 100 yards, best 4 of 8 groups. Differential between average groups of ammunition types was only 0.16-inch!

Then the skies opened up and the rain came down. I didn’t even get to peep the groups; just tore down the targets. I had to get outta Dodge before the range road became the Rio Poquito.

At home and warmed up, I was semi-stunned and definitely tickled when I peeled my soppin’ wet targets apart. I checked online and found many shooters were getting minute-of-angle groups with .300 Blackout supersonic, and others—mostly using bolt guns and handloads—were shooting 1/2-MOA groups. Most of those were 3-round groups. Mine were all 5-rounders. Given the conditions, I’ll take groups running 2 inches or less all day long. The premium ammo really delivered for me too.

I used Barnes VOR-TX featuring a 120-grain TAC-TX slug, G2 Research’s .300 Rip-Out 110-grain JHP’s, and HPR Ammunition’s 110-grain TAC-TX loads. Their listed velocity is 2,100 fps, and they shot so consistently as to be virtually indistinguishable. Their points-of-impact were extremely close, and obviously, they all bucked stout crosswinds just fine.

One note about magazines: .300 Blackout is supposed to be compatible with all standard 5.56mm mags. But, the contours of followers vary, so “standard” is a loose term. I had feeding problems with two types, and excellent performance with MagPul P-Mags and Brownells military-contract metal magazines, both in 20-round configuration.

Best Supporting Actor awards go to Leupold and Harris Engineering. The Mark 4 MR/T scope was up to Leupold’s usual superior performance, with outstanding light transmission and precise controls. Eye relief is very forgiving of slight changes in head position, and its illuminated reticle proved great for low-light snap shooting. One really useful feature is the illumination-off stop between each brightness setting. With ’em, you’re never more than one click away from your personal default setting.

No matter what game you’re after under what conditions, I highly recommend the Harris Ultralight Series S bipod, model BRM, mated to the Ambush .300’s 6 o’clock rail with a GG&G Harris Bipod Adaptor. Light, tough, stable and fully leg-length adjustable, it can make or break those critical shots.

All in all, this was a pleasant and productive introduction to the Ambush Arms rifle and the .300 Blackout cartridge. I don’t know if I could have done better with the platform, optic, ammo and bipod used, because this setup was, I think, a “gold standard” combo. I know there are other applications, but if you wanna bring home the bacon and pile up the pork chops, this is the gear to do it with.

There are no feral hogs around here (not enough potable water, dirt or foliage for more than stunted snakes and dehydrated lizards). But 200 miles to the south, wild piggies reproduce like Baltimore rats. Landowners welcome “harvesters,” and April prime time ain’t that far off. I like bacon. Hmmm… Connor OUT

.300 Blackout
Maker: Ambush Arms
101 Warfighter Way, Black Creek, GA 31308
(855) 262-8742

Action type: Direct gas, semi-auto
Caliber: .300 AAC, Capacity: 5 (accepts AR magazines)
Barrel length: 16 inches
Overall length: 32.5-inches, 35.75 inches extended
Weight: 6.9 pounds
Finish: Realtree AP camo (tested), black
Sights: None, Picatinny rail installed
Stock: Collapsible, rubber overmolded
Price: $1,799

Mark 4 MR/T 1.5-5x20mm Illuminated
Maker: Leupold & Stevens
14400 Northwest Greenbriar Parkway
Beaverton, OR 97006
(503) 646-9171

Magnification: 1.5X-5X, Objective diameter: 1.2 inches
Eye relief: 4.4 inches (1.5X), 3.7 inches (5X)
Internal adj. range: 120 MOA elevation, & windage at 100 yards
Click value: 1/2 MOA, Tube diameter: 30mm
Weight: 18 ounces, Overall length: 9.8 inches
Reticles: Blackout illuminated
Price: $1,749.99

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