Ruger’s American Predator rifle is a great bolt-gun package in 6.5 Grendel, and it uses AR-pattern magazines, too!
Built especially for an AR, the 6.5 Grendel cartridge and rifle combination has the terminal ballistics that works well for whitetails and competition, and the choice of Modern Sporting Rifle packages is pretty broad.
The final leap for the 6.5 Grendel came in February 2012, when Alexander Arms relinquished their trademark claim on the cartridge’s name and it is awarded as a firearms industry standard round with the Sporting Arms and Ammunition Manufacturers’ Institute (SAAMI). Since then, a few manufacturers have put the 6.5 Grendel into bolt actions, and the latest is Ruger’s American Predator.
After testing a half dozen AR-platform rifles in 6.5 Grendel, I’ve got a pile of brass that’s begging for fresh powder, bullets and primers. Crafting handloads for this light-weight bolt-action rifle is the next logical step.
Ruger’s American Grendel
The first time I laid hands on a Ruger American in 6.5 Grendel at the 2018 SHOT Show, I marveled at the compact little rifle… with an AR magazine. I always had the impression that the company’s founder wasn’t impressed with AR rifles, and putting a STANAG magazine in one of his company’s bolt guns was a real departure from the norm.
This moss green synthetic-stocked gem sports a 1:8 twist 22-inch barrel that tips the scales at 6.6 pounds. The fact that it sports a threaded muzzle would allow me to use a 5/8-24 TPI silencer, too.
Reloading & Range Time
Shooting the Ruger American Predator 6.5 Grendel proved frustrating at the beginning of the process. Several groups down range showed promise, but several 5-shot groups at 100 yards showed a trend to cluster shots within a group about 2 ½ inches apart. After more than 50 rounds down range, the scope was changed from a 3-9X Burris to a Trijicon 5-20X Aimpoint. While the optic was off the rifle, the scope base was checked and the screws were found to be loose. A couple of drops of thread locker applied, the scope base screws were tightened back down to 30 inch-pounds. Thinking the problem was solved, more targets were tacked up and rounds sent down range. It continued to produce twin bullet-hole clusters, so something else was amiss.
The next thing I did was disassemble the rifle to check the bedding. Everything checked out okay, so I reassembled it properly torqueing the action screws.
At the beginning of the process I attached an Advanced Armament Corporation SDN-6 51-tooth fast-attach muzzle brake to take advantage of the Ruger’s threaded muzzle. The last group fired was measured 4.714 inches. Thinking that the less-than-secure attachment between the brake and the suppressor might be the cause, I removed it and fired another group that wasn’t much better. Thinking back to when I was testing Remington’s Precision Sniper Rifle SOCOM contender with Robbie Johnson out in Cour d’Alene, Idaho, a few years ago, I asked Robbie why the fast-attach suppressor on his test rifle wasn’t an AAC product. He shared that the muzzle brake attachment was causing a degradation of accuracy and that AAC was working on a fix at the time. When I replaced the muzzle brake with an AAC Cyclone, which is a direct-thread 5/8-24 TPI silencer, things changed dramatically. The next group with the same load measured 0.497-inch! Found the problem.
Prior to finding the accuracy problem associated with the muzzle brake, I had begun work on bullet seating depth variations to try to fix the problem. Starting over after switching silencers, I did detect some minor improvements when seating bullets closer to the point in the chamber throat where the bullet’s ogive made contact. Using a Hornady Bullet Seating Depth Comporator, I took a Hornady 123-grain A-Max and pushed it to the point of chamber throat contact. The resulting over-all length (OAL) was 2.368 inches.
The maximum length that this bullet can be seated and not make contact with the front edge of an AR magazine is 2.300 inches. The difference is a pretty substantial jump. I typically seat bullets with 0.010 to 0.020 off the lands/throat for .264 caliber bullets, but I didn’t have that choice if I wanted to use STANAG magazines. But, as well as it was shooting with 0.068 jump it was moot. Another positive to keeping bullet seating depth at magazine length or less it would allow use in a mag-fed AR, too.
Now that the rifle’s accuracy maladies were solved, I picked three factory loads to shoot to establish a base line from which to work. The first load was Wolf’s 120-grain, which produced a 5-shot group at 100 yards that measured 1.287. Hornady’s factory load of 123-grain SSTs produced a group measuring 0.800 inch. Next up was Hornady’s factory loaded 123-grain A-Max, which produced a best 5-shot group measuring 1.107 inches.
Finding a Recipe
Four powders and seven bullets were selected to trial for the Ruger American 6.5 Grendel. My objective was to find a good whitetail and coyote load. Five-shot groups at 100 yards from a concrete-reinforced bench and front and rear bags provided stability.
The first load was a 100-grain Nosler Partition and 30.2 grains of TAC. The first load was seated to an OAL of 2.185 inches. This load produced a 1.407-inch group. Seating the next load out to 2.245 inches yielded a 1.110-inch group. Going to 2.297 OAL produced a group of 1.697.
Swapping to a 100-grain Hornady A-Max with 30.2 grains of TAC seated out to an OAL of 2.300 produced groups that hovered around a half-inch. The best group measured 0.497. Stepping up to 30.5 grains of TAC with the same bullet enlarged groups to 0.908. Going up to 31.5 grains of TAC showed signs of flattened primers and an ejector mark on the case head after one shot, so I quit loading at that level.
Stepping up bullet weight to a 123-grain Hornady SST and 27.8 grains of TAC with an OAL of 2.290 yielded a group measuring 0.567.
The same 27.8 grains of TAC driving a 123-grain A-Max yielded groups averaging more than 1 MOA.
Swapping to Accurate 2520, I worked up to 29.1 grains before showing pressure signs, and several groups fired with that load averaged 1.534 inches. The smallest group measured 1.118. These were seated to 2.297 OAL.
The next powder tried was W748 with the 129-grain SST. Working up to a load of 29.0 grains with bullets seated to 2.297 inch produced a sub-MOA average, with the best group measuring 0.634-inch.
Staying with the 129-grain SST, the powder was swapped to IMR 8208 and loads worked up to 29.0 grains with bullets seated to 2.294 inches. This load averaged 0.585, with the smallest measuring 0.430.
The ideal bullet weight for the 6.5 Grendel is 123 grains, according to all of the testing Hornady conducted when perfecting factory loads. With some rifles, a 130-grain bullet will produce acceptable accuracy and target energy. With that in mind, I loaded Berger’s 130-grain VLD Hunting bullets. The first load was 28.5 grains of Accurate 2520. Accuracy was spectacular, with the smallest group going 0.639 of an inch.
Switching powders to IMR 8208 made things interesting. A 26.2-grain load driving a Hornady 129-grain SST stayed sub-MOA. The best group fired measured 0.430, and was the smallest of any load tested.
Checking the velocity data from the accompanying chart shows quite a variation in muzzle velocities between various loads and powders. It’s a tossup between the 100-grain A-Max and the 123-grain SST, both loaded with Accurate TAC. I’ll probably load the lighter bullet for varmints and the heavier for deer this coming season.
I’ve tested quite a few rifles in 6.5 Grendel over the years that can produce half-MOA groups, and some of them approach 10 times the price of this little Ruger American. You may want to get your hands on one, too, and spend some time at the reloading bench with the 6.5 Grendel.
| Manufacturer | Bullet | Wt. Gr. | Powder/wt. | Velocity | OAL | Group Size |
| Hornady | ELD Match | 123 | A-TAC/27.8 | 2,452 | 2.288 | 0.628 |
| Hornady | SST | 123 | A-TAC/27.8 | 2,429 | 2.290 | 0.567 |
| Hornady | A-Max | 123 | A-TAC/27.8 | 2,433 | 2.297 | 1.345 |
| Berger | VLD Hunting | 130 | A-2520/28.5 | 2,415 | 2.295 | 0.639 |
| Hornady | A-Max | 123 | A2520/29.1 | 2,539 | 2.997 | 1.118 |
| Hornady | SST | 129 | W748/29.0 | 2,383 | 2.997 | 0.634 |
| Hornady | SST | 129 | IMR 8208/26.2 | 2,290 | 2.294 | 0.430 |
| Hornady | A-Max | 100 | A-TAC 30.2 | 2,737 | 2.300 | 0.497 |
| Hornady | A-Max | 100 | A-TAC 30.5 | 2,741 | 2.300 | 0.857 |
| Nosler | Partition | 100 | A-TAC 30.2 | 2,724 | 2.245 | 1.110 |
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