6mm HAGAR

The 6mm HAGAR started out as a target cartridge for AR rifles, winning several National High Power Championships and is currently showing great promise as a varmint cartridge. Hornady manufactured cases and reloading dies, and plenty of data is available, so shooters can readily handload this wildcat cartridge.

The 6mm HAGAR was developed in 2003 by match rifle shooter John Harrison and gunsmith Sid Goodling. HAGAR is an acronym for Harrison and Goodling Automatic Rifle. It’s been stated the 6mm HAGAR is nothing more than the 6.8 Remington SPC case necked down to hold .24-caliber bullets. AR-X Enterprises in Doylestown, Pennsylvania, sells HAGAR brass and dies, and Justin Whitley of AR-X said the 6mm HAGAR case is similar to the 6.8 Remington SPC but longer and thinner. The 6mm case is 1.765 inches in length, while the 6.8 is 1.676 inches long. The 6mm’s case body is also slimmer, and its rim diameter is a smidgen narrower at .412 inch, compared to the 6.8’s .422-inch diameter. Near as I can measure, the HAGAR has only .011 inch of case body taper, about the least of any bottleneck cartridge.

New Hornady HAGAR cases measured 1.780 inches long. Maximum case length is 1.775 inches, so sample cases were cut to a trim length of 1.765 inches. After firing, the cases had not stretched any appreciable amount, nor did they noticeably stretch after full-length sizing.

Justin Whitley said his father, Robert Whitley, has been a competitive handgun and rifle shooter for years. High Power Rifle shooting was one of Robert’s hobbies, and he started modifying AR uppers to improve accuracy with the help of a gunsmith friend with a machine shop. Before long, customers started coming to him to fix their rifles, and Whitley’s uppers and AR-X was born about 10 years ago.

AR-X makes match and varmint-style AR uppers in 6mm HAGAR. Justin said the uppers are built with tight tolerances and fitting of parts to assist in shooting .50-inch groups at 100 yards. The Varmint rifle used here to test loads is made with a heavy-walled upper receiver and side-charging handle attached to the bolt. According to AR-X’s website, 6mmar.com, the receiver walls of military-style uppers are thin, which make them prone to flexing when the rifle fires. The receiver walls of AR-X’s uppers are three to four times thicker to make the receiver rigid to improve accuracy.

To further stiffen the receiver, the barrel extension is locked in place, front to back, in the receiver and makes the barrel nearly an integral part of the receiver. The ventilated aluminum handguard is 2.25 inches in diameter, is free-floated and very rigid to counteract any flex when the handguard is on a rest or attached to a bipod when the rifle fires and the carrier begins to cycle.

The rifle’s 24-inch stainless steel Pac Nor barrel is an inch in diameter under the handguard and tapers to .975 inch in front of the gas block, and it keeps that diameter out to its muzzle. Barrel lengths of 20, 22 and 26 inches are also available. A Sabreco muzzle brake is threaded onto the muzzle. The brake so exactly matches the barrel, it’s nearly impossible to determine where the two meet. The Varmint rifle upper has a flat top with a slotted rail to attach sights. I clamped a Leupold Mark 4 3.5-10x 40mm LR/T scope on the rail. With the scoped upper pinned in an AR lower, the whole outfit weighed 11 pounds, 12 ounces.

The HAGAR’s supposed maximum cartridge length is 2.26 inches, so cartridges fit in magazines intended for the 6.8 SPC. A bullet and 30-some grains of powder are a tight fit in the HAGAR case with that cartridge length. However, nothing is definite about wildcat cartridges, and AR-X supplies magazines modified to accept cartridges with a length of up to 2.34 inches. To afford a slight amount of wiggle room in the modified magazine, all my loaded HAGAR cartridges had a length of 2.295 inches.

The AR-X’s Varmint barrel has a one-in-12-inch rifling twist. That twist will stabilize 6mm bullets weighing up to 80 grains. The barrel’s chamber throat is also cut to accept bullets up to that weight.

AR-X’s website lists powder weights for the HAGAR for 55- through 70-grain bullets for barrels with a one-in-12-inch twist and bullets weighing up to 105 grains for Match barrels with 1-8 twist rifling. I loaded bullets from 55 to 80 grains for the Varmint’s 1-12 twist. The website also lists load data for these bullet weights with Benchmark; H-322; IMR-8208 XBR; Vihtavuori N133, N140, N540; and Reloder 15 powders.

The HAGAR’s total case capacity was measured and was nearly the same as the 6mm Benchrest case. So some of the loads used in testing the HAGAR were a couple of grains below maximum for the 6mm Bench-rest as listed in various reloading manuals for Accurate 2460, IMR-3031, LT-32, TAC, Varget, W-748 and X-Terminator propellants.

With cases from AR-X and a set of Hornady reloading dies, a variety of 6mm HAGAR cartridges was assembled. All the handloads performed well. Out of 24 three-shot groups fired at 100 yards from a bench, only three measured over an inch. One morning I had 26 cartridges loaded with Nosler 70-grain Ballistic Tip bullets and LT-32 powder. One right after another, the rifle placed 10 bullets in a 1.43-inch group at 100 yards. Eight more quick shots landed in 1.06 inches. I fired the final eight cartridges in about 10 seconds, and they landed in 1.31 inches. A total of about 200 rounds were shot through the AR-X rifle, and every one cycled perfectly. Ejected cases stacked up in a neat pile on the ground behind and to the right of the rifle.

The light 55-grain bullets had the highest extreme velocity spreads. Those spreads varied from 70 fps with LT-32, 96 fps with H-332 and 106 fps with Benchmark. Velocity swings, however, were much less with 60-grain and heavier bullets. Nosler 70-grain Ballistic Tips varied only 7 fps for three shots with Benchmark. Hornady 75-grain V-MAX bullets wavered only 22 fps when shot with W-748 powder, and Berger 65-grain bullets differed but 13 fps when used with Vihtavuori N133. Overall, the most consistent velocities and best accuracy came from Benchmark, IMR-3031, VV-N133, LT-32, W-748 and X-Terminator.

The HAGAR burns only about 30 grains of powder. Consuming that much powder, it shot 55-grain bullets at 3,432 fps, 65-grain bullets at 3,245 fps and 70-grain bullets at 3,156 fps. Those velocities are right in line with those listed on AR-X’s website. My powder charges could have been increased a grain or two. The velocities from the loads I used, though, are comparable to those delivered by the 6mm PPC and 6mm Benchrest cartridges that use similar amounts of the same powders. The much larger 243 Winchester burns five to seven grains more powder to equal the HAGAR’s velocities. Unlike these other three 6mm cartridges, the HAGAR fits and cycles nicely in an AR rifle.

The HAGAR burns about three to five grains more of the same powders as the 223 Remington, with both shooting the same weight bullets, but the HAGAR turns in roughly 100 fps of additional velocity over the 223 for that extra powder. The 223 Remington is known for its long barrel life. The 6mm HAGAR, also burning moderate amounts of powder and with a slightly larger barrel bore, should also provide a similarly long barrel life.

The AR-X 6mm HAGAR’s recoil was but a pat on the cheek with its heavy weight and muzzle brake in place. The rifle moved so slightly when it fired that I often saw bullet holes appear in the targets. Recoil was mild, even with the muzzle brake removed.

I carried the AR-X rifle coyote hunting one fall morning. While walking across sagebrush flats, the rifle was bearable while suspended on my shoulder with a sling, but it was a burden when climbing hills. The rifle was steady and quick to aim when supported on shooting sticks, but I never fired it that day, because the coyotes were somewhere else. The AR-X Varmint rifle is best supported on a bench overlooking a prairie dog town or rock canyon full of marmots. Shooting 55-grain bullets at top speed, only a bit of holdover is required for hits at 300 yards.

Whether the 6mm HAGAR will develop enough of a following to keep it alive depends on several factors. Varmint hunters will have to carry its freight, because there are 20 times more varmint hunters than target shooters. Several other manufacturers of AR uppers are chambering the 6mm HAGAR, so rifle choices are increasing. Plus, a bolt-action rifle would add further variety and may allow assembling increased-pressure handloads. As long as Hornady makes a run of HAGAR cases now and again, the cartridge will keep handloaders delighted with its great accuracy and acceptable velocity from a moderate amount of powder.