- What the SP10M is: Seekins Precision’s custom-shop version of the SP10 large-frame AR, built to a tighter accuracy standard than the standard catalogue rifle.
- Accuracy claim: three-quarter-MOA tested accuracy, verified per rifle rather than advertised as a platform average.
- Chamberings: .308 Winchester and 6.5 Creedmoor.
- Suppressor-friendly: an adjustable gas block, which is what lets a large-frame gas gun run a can without beating the bolt.
- What we stock: not the SP10M custom-shop rifle, but Seekins Precision Element Hunter .308 rifles and their AR parts — low-profile gas blocks, DNA charging handles and NOXs M-LOK rails. Order online, rifles ship to your local FFL and parts ship to your door.
AR-10s are half my workbench. I’m Lance Rankin, owner and gunsmith at Western Sport in Roanoke, Texas, and large-frame gas guns are a specialty of mine, so the Seekins SP10M, the rifle that earned a SOCOM designated marksman and sniper role, has my full attention. The range time in the video above belongs to its creator; the numbers below come from that footage, and the workbench commentary is mine.
Seekins SP10M: the short answers
- SP10 vs SP10M: Same platform, different acceptance standard. The M is the military-specification build, gauged and inspected at every stage including after coating, where the civilian SP10 runs Seekins’ normal commercial process.
- Why that difference matters: The large-frame AR never had a true mil-spec standard, so stacked tolerances are where AR-10 accuracy is lost. Gauging every interface is the fix.
- Calibers: 6.5 Creedmoor and .308 Winchester, with .260 Remington turning up occasionally.
- Military role: SOCOM selected the SP10M for a designated marksman and sniper role. It is a semi-automatic precision rifle, not a bolt-gun replacement.
- Measured accuracy: About 0.72 MOA in 6.5 Creedmoor with 140-grain Sierra MatchKings and about 0.79 MOA in .308 with 168-grain SMKs, both tightening with a preferred load.
- Barrel life tradeoff: 6.5 Creedmoor throats wear faster than .308. Shoot far with the 6.5; shoot high volume with the .308.
- Gas system: Adjustable, a single lever flip, which is what keeps it running when the rifle is filthy or the ammunition is inconsistent.
- How to buy one: Any Seekins dealer can order it, and any FFL can receive one you buy online. Western Sport does both — order online and we ship it to your local FFL.
What separates the SP10M from a regular AR-10
At a glance it’s a familiar shape: AR-pattern, direct impingement, 20- or 25-round box mags, offered in 6.5 Creedmoor, .308, and occasionally .260 Remington. The difference between the civilian SP10 and the military-spec SP10M is mostly invisible: obsessive inspection and gauging at every stage, with parts checked, re-checked, and checked again after coating. That sounds like marketing until you’ve built precision gas guns yourself. Stacking tolerances is exactly where AR-10 accuracy goes to die, because unlike the AR-15, the large-frame platform never had a true mil-spec standard. Everyone’s “AR-10” is a little different, and sloppy interfaces cost you at the target. A manufacturer that gauges everything is solving the platform’s actual weakness.
The numbers from the range
Per the video: the 6.5 Creedmoor printed around 0.72 MOA with 140-grain Sierra MatchKings, dipping to half-MOA on good days. The .308 ran about 0.79 MOA with 168-grain SMKs and reportedly tightened to 0.4 with its favorite load. Recoil in both was soft enough to spot your own impacts, and the adjustable gas system is a simple lever flip. At 1,000 yards, hits came fast, with the 6.5 pulling ahead of the .308 past 900 as ballistics say it should. The heavy barrel held its accuracy through long strings, and mid-range work from 350 to 650 yards was quick and unremarkable, which is the compliment you want from a DMR.
Those groups from a semi-auto .30-cal-class rifle are legitimately excellent. A bolt gun will still edge it for pure precision per dollar, but the entire point of a precision gas gun is fast follow-ups and target-to-target speed, and this delivers both.
Durability and the 6.5 tradeoff
SOCOM testing reportedly ran these rifles thousands of rounds before groups opened past 1 MOA. One honest note the review included, and I’ll echo from experience: 6.5 Creedmoor barrels wear faster than .308 barrels. That’s physics, not a Seekins flaw; hot, efficient calibers eat throats. If you shoot high volume, a .308 barrel lives longer. If you shoot far, the 6.5 earns its keep. The adjustable gas block also means that when the gun gets filthy or the ammo gets weird, you turn a lever instead of fighting malfunctions.
The reviewer ran it with a Harris bipod, Nightforce ATACR and Tangent Theta glass, and a PEQ-15 with a clip-on thermal for night work. Duty-grade accessories on a duty-grade rifle; no argument from me, though the glass on that setup costs more than the rifle.
Should you buy one?
At roughly $3,000, the SP10M sits in a strange sweet spot: real money, but well under the $5,000-plus tier of high-end AR-10s, with accuracy that embarrasses some of them. If you want a semi-auto rifle for long-range steel, hog problems at distance, or just because SOCOM’s pick is a fine excuse, it’s a strong buy. If your budget’s tighter, remember the truest line in the whole video: skill beats gear. A $1,500 rifle with $1,500 of ammo and practice outshoots a $3,000 rifle in a safe.
Large-frame builds, precision work, and optics mounting are daily business at my bench, and I can order Seekins to your local FFL or transfer one you find online. My FFL transfer explainer covers the process ($40 plus $10 NICS), and if you’re weighing platforms first, my AR-15 vs AK-47 and Daniel Defense vs BCM writeups are good background. Call 817-393-4000 or email [email protected].
Lance Rankin is the owner and Chief Gunsmith of Western Sport, a family-run Type 07 FFL and Class 3/SOT dealer in Roanoke, Texas, serving shooters since 2007. Born and raised in Texas with over 50 years of experience handling firearms, Lance purchased Western Sport in 2017 and turned his lifelong passion into his profession. He specializes in AR-15 and AR-10 platform rifles, manufactures Western Sport’s own AR-15 line under the Rankin Industries brand, and runs the shop’s in-house Cerakote coating operation. When he’s not behind the counter or the workbench, you’ll find him on his ranch deep into the night, hunting coyotes with an AR-15 and thermal optics. Lance holds an MBA and personally shoots and tests the products Western Sport sells.
