The 6.8 SPC was developed after the U.S. Special Operations Command (USSOCOM) shelved a program to create a modular, special-purpose rifle that could fire both 5.56mm NATO and 7.62x39mm ammo. During that program, USSOCOM discovered that the 7.62x39mm had slightly better terminal performance than the 5.56mm—exactly what many operators in Iraq and Afghanistan had also noticed.

The Enhanced Rifle Cartridge (ERC) program rolled out of the modular rifle program and was headed up by USSOCOM and aided by Remington. To develop the 6.8 SPC, a shortened .30 Remington case was used with a .270 bullet—the same bullet used in the .270 Winchester cartridge. This bullet has a good ballistic coefficient (BC) with less air resistance in flight, good accuracy and plenty of downrange energy.

“This bullet has a good ballistic coefficient … with less air resistance in flight, good accuracy and plenty of downrange energy.”

More rifles and carbines currently made in 6.8 SPC have a Spec II chamber. By 2004, civilians had access to the 6.8 SPC, and the round has become a popular AR caliber for hog and deer hunters as well as those serious about personal and home defense. The Saudi government’s armed forces also use the 6.8 SPC. Since the round was designed to fit in the AR-15 platform, only a few internal components are different than the 5.56mm’s: the bolt head, magazine and barrel.

Accuracy and terminal ballistics matter. Here are some of the best 6.8 SPC rifles and carbines available on the market today.

Ambush 6.8 SPC II

The Ambush 6.8 SPC II, designed by Ambush Firearms, a sister company of Daniel Defense, features a cold-hammer-forged, 18-inch barrel with a 1-in-11-inch twist rate. It carries a free-floating, 12-inch MFR handguard with an adjustable foregrip, a Geissele SSA two-stage trigger and their new, enhanced furniture. (ambushfirearms.com; 855-262-8742)

2 Vets Arms 6.8 DMR

The 2VA 6.8 DMR from 2 Vets Arms is built with a 7075-T6 billet, side-charged upper receiver and uses a 20-inch, 416R stainless steel barrel with an intermediate-length gas system. The forged 7075-T6 lower receiver uses an adjustable two-stage trigger. 2 Vets Arms is a service-disabled, veteran-owned business (SDVOB) that specializes in developing and building high-performance custom rifles, and the 2VA 6.8 DMR is just that. (2vetsarms.com; 918-799-5186)

ArmaLite M-15A4

Armalite is the original creator of the AR, and the M-15A4 in 6.8 SPC is built with a mid-length handguard and gas system. The double-lapped, chrome-lined barrel, optimized for 110- and 115-grain bullets, has a 1-in-11-inch twist rate. (armalite.com; 800-336-0184)

Barrett REC7 Gen II

The REC7 Gen II is a well-tuned piston-driven rifle that is fast cycling and totally reliable. It has a slim, octagonal KeyMod handguard that offers a comfortable handhold. Barrett decks out the REC7 in quality parts, including a PWS Triad flash suppressor, Magpul’s MOE stock and pistol grip, Precision Reflex flip-up sights, a Bravo Company Manufacturing Gunfighter charging handle, a Geissele trigger and more. It is well balanced and built for accurate, rapid fire. Barrett rifles its 6.8 SPC barrels with a 1-in-10-inch twist rate. (barrett.net; 615-896-2938)

Bushmaster ACR

The Bushmaster ACR (Adaptive Combat Rifle) is a next-generation combat rifle that has AR-like controls but features well beyond the AR, like a multi-caliber bolt assembly that allows calibers to be swapped and an adjustable, two-position gas piston system that supports suppressed and non-suppressed fire. The stock is fully adjustable to fit most statures and it folds, making the ACR highly maneuverable. (bushmaster.com; 800-998-7928)

DoubleStar Supermatch

The DSC Supermatch is outfitted with a heavy stainless barrel that is either 20 or 24 inches with a 1-in-8- or 1-in-10-inch twist rate. The heavy barrel is free-floated in a DSC rifle-length handguard, and a rifle-length gas tube keeps this 6.8 SPC rifle running and producing sub-MOA groups. (star15.com)

DPMS Prairie Panther

Hogs or whitetails—take your pick, since the Prairie Panther in 6.8 SPC can handle either with ease. This rifle is lightweight even with a 20-inch, fluted barrel made of 416 stainless that is Teflon coated. A carbon-fiber tubular handguard free-floats the barrel for optimal accuracy. The rifle is an optics-ready flattop design. (dpmsinc.com; 800-578-3767)

LMT CQB MRP Defender Piston

The CQB MRP Defender Piston features a piston operating system that runs cleaner and cooler than the direct impingement system. The 6.8 SPC barrel, cryogenically treated for enhanced accuracy, has a 1-in-10-inch twist rate. The monolithic MRP upper also offers quick barrel changes. (lmtdefense.com; 309-787-7151)

LWRCI Six8 A5

LWRCI rifles use a patented self-regulating, short-stroke gas piston system that not only keeps the bolt carrier cool and clean, but it also helps improve handling, since the recoil is lighter. LWRCI equips its Six8 line with cold-hammer-forged barrels with 1-in-10-inch twist rates. The newest model is the A5, which is essentially the same as the IC-A5 but with a two-position gas block. Up until now, Six8 A5s have been limited runs, but their popularity means they will become a standard catalog item in 2015. (lwrci.com; 410-901-1348)

Rock River Arms LAR-6.8 X-1

Rock River Arms (RRA) has updated its LAR-6.8 series with the X-1, a rifle featuring an 18-inch, stainless barrel with a 1-in-10 twist. It sports RRA furniture like the Operator CAR or A2 stock, a two-stage trigger, the Beast or Hunter muzzle brake and the TRO-XL free-floating handguard. The rifle comes with a 1-MOA accuracy guarantee at 100 yards. (rockriverarms.com; 866-980-7625)

Stag Arms Model 5

The flattop Model 5 from Stag Arms comes optics-ready for mounting scopes or sights. The thermoplastic handguard and AR-style pistol grip are similar to an M4’s. The barrel for the Model 5 has a 1-in-11-inch twist rate. Swapping out an upper is an easy deal since Stag Arms uppers are compatible with mil-spec lowers. (stagarms.com; 860-229-9994)

Wilson Combat Recon SR Tactical

The Recon SR Tactical features forged 7075-T6 upper and lower receivers. The barrel is a 14.7-inch, medium-weight, stainless steel, match-grade unit with M4 feed ramps. The muzzle sports either a permanently mounted Rapid Threat attachment or a permanently attached Accu-Tac flash suppressor for a total barrel length of 16.1 inches. Surrounding the mid-length gas system and low-profile gas block is Wilson Combat’s TRIM rail. (wilsoncombat.com; 800-955-4856)

Yankee Hill Machine Model 57

Yankee Hill Machine (YHM) builds high-quality ARs that undergo a strict quality control process. The company offers a variety of 6.8 SPC carbines, including the Model 57, YHM’s standard billet AR which features next-gen styling, plenty of fluting for lightweight handling characteristics and an interesting handguard with short rail sections and a long top rail for mounting optics. (yhm.net; 877-892-6533)