Best Scopes for AR-10 & .308 Rifles 2026

A large-frame .308 asks three things of an optic: enough rearward eye relief to survive its recoil impulse, a weight it can afford on a 9 to 11 pound rifle, and enough elevation travel to cover .308 trajectory out to the distance you actually shoot. Those three constraints, plus where the mount sits on the upper receiver, decide this purchase.

Recoil sets the eye-relief floor. Gas operation spreads a .308's impulse out and takes the peak off it, so a semi-auto is gentler than a bolt gun in the same chambering. It still moves roughly twice the impulse of a 5.56 carbine, and the margin between your eye and the ocular is what absorbs that. Treat eye relief as a fit-and-safety check you clear in your own firing position at maximum magnification, then rank on what the rifle is for. The Vector Optics Continental x6 2-12x44 RAR gives the most back at four inches, the Vortex Strike Eagle 3-18x44 gives 3.8, the Steiner H6Xi 3-18x50 runs 3.85 inches at the low end to 3.52 at the top, and the Primary Arms PLxC 1.5-12x36 runs 3.3 to 3.6. The EOTech Vudu 4-12x36 is the tightest of the eight because EOTech publishes it per magnification: 2.5 to 3.1 inches at 4x and 2.4 to 3.0 inches at 12x. That is the Vudu's main drawback on a recoiling .308, and it is the price of its 7.1-inch body.

Weight is not an abstraction on a large-frame rifle. An AR-10 already starts heavier than a 5.56 carbine, so a 27-ounce scope is a meaningful share of the total before you add a mount, and a 39-ounce scope changes what the rifle is for. The EOTech Vudu 4-12x36 at 16.9 ounces and the Primary Arms PLxC at 19.67 are the two picks that leave the rifle handling like a carried gun. The Vector Continental x6 at 27.1, the Steiner H6Xi at 27.4, and the Nightforce ATACR 4-16x42 F1 at 30.0 sit in the middle. If you are still choosing the host rifle, the AR-10 rifle ranking and the broader .308 rifle guide cover what those rifles weigh before glass.

Elevation travel is what you spend on .308 drop. If you hold rather than dial, a first-focal-plane reticle carries the work and travel matters less. If you dial, what matters is not the cartridge label but how much upward travel is left above your zero. .308 is not uniquely steep here: with a 200-yard zero, Federal puts 168-grain .308 at 51.5 inches of drop at 500 yards, against 54.1 inches for 77-grain .223 and 46.4 inches for 140-grain 6.5 Creedmoor. Compare your load's required come-up against the travel that remains after zeroing, not against the total on the box. The Primary Arms PLxC and the SIG Sauer Tango-MSR 1-10x26 FFP each carry 100 MOA. The Vector Continental x6 carries at least 63 MIL behind a zero stop, the widest figure in this field. The Vortex Strike Eagle 3-18x44 carries 45 MRAD total, though installing RevStop leaves 19.4 MRAD above zero on the MRAD model, and the Nightforce ATACR 4-16x42 F1 carries 26 MRAD, or 89 MOA, behind a ZeroHold turret. The Steiner H6Xi's MHR variant carries 75 MOA of total elevation, less than the picks built around dialing.

For a general-purpose .308 that has to work close as well as far, buy the lowest low end you can live with: the SIG Sauer Tango-MSR 1-10x26 FFP at 1x or the Primary Arms PLxC 1.5-12x36 at 1.5x. For a supported rifle that gets dialed, buy travel and top-end reach: the Vortex Strike Eagle 3-18x44 or the Nightforce ATACR 4-16x42 F1. For a bipod-fed designated marksman rifle, the Arken EP-5 5-25x56 is the specialist. Those three sentences cover most of the decision, and the rest of this section is the arithmetic behind them.

The low end decides close-range usability. The SIG Tango-MSR opens at a true 1x with a first-focal-plane MSR BDC-10 reticle. The Primary Arms PLxC opens at 1.5x, which is not a true 1x but keeps a wider field of view than everything above it. The Vector Optics Continental x6 opens at 2x. The Vortex Strike Eagle and Steiner H6Xi open at 3x, which is slower for close unsupported shots. The EOTech Vudu and Nightforce ATACR open at 4x, and the Arken EP-5 at 5x, which puts both of the last two on rifles whose closest realistic target is already well out.

Top-end reach is what you pay ounces for. The PLxC and Continental x6 stop at 12x, the Vudu at 12x in a 7.1-inch body, the ATACR at 16x, the Strike Eagle and H6Xi at 18x, and the Arken EP-5 at 25x. Every step up the top end costs field of view and mass: the Strike Eagle is 26.6 ounces and the H6Xi is 27.4 against 19.67 for the PLxC. On a rifle that is already 9 to 11 pounds loaded, that is the trade to argue with yourself about before you argue about glass. For the ranking that treats top-end reach as the primary axis rather than a trade, see the long-range rifle scope guide.

Hunting and low light pull toward the bigger objectives. The Steiner H6Xi 3-18x50 is the hunting-lean pick here: a 50mm objective, 92% light transmission, first-focal-plane MHR or STR MIL reticle options, and a side focus that adjusts from 25 yards to infinity. Its cost is 27.4 ounces on a carryable AR-10 and 75 MOA of elevation in the MHR variant, less than the scopes built around dialing. The Nightforce ATACR's 42mm objective and the Vudu's 36mm give up light-gathering area to it, which is the other half of the same trade.

One LPVO belongs in this field, and it brings its own mount. The SIG Sauer Tango-MSR 1-10x26 FFP is the only true 1x option here, with a first-focal-plane MSR BDC-10 reticle, 100 MOA of elevation travel, 11 illumination settings, and 21.9 ounces. It ships with the ALPHA-MSR one-piece aluminum cantilever mount, which settles the mounting question in the same box. Its eye relief is 3.54 inches at low power and 3.22 at high, shorter than the four-inch options, and 1-10x gives up top-end detail to the dedicated 12x through 18x scopes. Take that trade when the rifle has to work close.

The Arken EP-5 is ranked last on purpose, and it is still a good scope. The Arken EP-5 5-25x56 FFP belongs on a long-range-focused AR-10 or a designated marksman rifle, not on a general-purpose .308. Two objective numbers say why: 39.2 ounces is wrong for a rifle you carry inside a 9 to 11 pound budget, and a 5x minimum magnification is wrong for anything that might have to shoot close. Judged as the DMR optic it is, it is a strong pick: 32 MIL or 110 MOA of elevation travel behind an AZS zero stop, an FFP VPR reticle, a 34mm tube, and a 56mm objective, all pointed at a bipod-fed supported position. Buy it for that rifle and it earns its place. Buy it for a do-everything .308 and the weight and the 5x floor will both bother you.

Put both mount contact points on the upper receiver's rail and start at an AR-height mount of roughly 1.3 to 1.5 inches. That is the whole starting recipe for AR-10 scope mounts. Everything after it is confirmation on your own rifle: objective clearance, charging-handle access, eye relief in your actual firing position, and a cheek weld you can repeat.

Receiver rail, not handguard. The upper receiver is the rigid reference the barrel is indexed to. A free-float handguard is a separate part clamped to the barrel nut, and a mount that spans from one to the other ties the optic to two structures that do not move together. When the scope needs to sit further forward than the receiver rail allows for comfortable eye relief, the correct fix is a cantilever mount that overhangs while keeping both of its clamps on the receiver. The SIG Tango-MSR includes exactly that type of mount at a 34mm tube diameter.

The exception is a monolithic upper. This rule describes the conventional build, where the handguard is a separate part. Some large-frame rifles instead use a monolithic upper whose rail runs continuously from the receiver over the handguard as one machined piece, among them the LMT MARS-H on its MRP-H receiver and the Colt LE901 modular carbine. There is no joint to straddle on those, so rings can sit forward on the rail without a cantilever. Check which of the two your upper actually is before you buy the mount.

Height is set by the objective, then confirmed by your face. An AR-height mount in the 1.3 to 1.5 inch range is the starting point on a large-frame AR. From there the objective bell decides whether it clears the rail: the 36mm Primary Arms PLxC and EOTech Vudu clear at lower heights than the 50mm Steiner H6Xi or the 56mm Arken EP-5, and a scope that will not clear needs height, not force. Then check that the charging handle still comes back without hitting the ocular, that eye relief lands where your head naturally sits, and that the cheek weld repeats shot to shot rather than requiring you to search for the sight picture.

Budget the mount with the scope, because the tube decides it. The Primary Arms PLxC and Steiner H6Xi use 30mm tubes. The Vector Continental x6, Vortex Strike Eagle, Nightforce ATACR, SIG Tango-MSR, and Arken EP-5 all use 34mm, so they need 34mm rings or a 34mm one-piece mount. The EOTech Vudu 4-12x36 uses neither: it mounts through an integrated base that works with most aftermarket mini-ACOG mounts, which is a different shopping trip than a ring set. If you intend to dial rather than hold, buy the base cant along with the rings: a 20 MOA canted mount spends none of the scope's internal travel to buy back roughly 20 MOA of usable come-up, which is the cheapest way to fix an elevation ceiling without changing scopes. For the torque values, leveling method, and ring-lapping question behind all of this, work through the optic mounting guide.