The 360 Precision Low Profile ARCA Rail 13″ is a full-length M-LOK-mounted ARCA dovetail rail designed for precision rifle and competition builds where maximum bipod slide travel matters. At 13 inches, it covers nearly the entire bottom of a standard 15-inch AR-15 handguard, giving you unrestricted fore-aft adjustment for bipods, tripods, plate clamps, and barricade adapters along the full length of the forend.

Mounts using five included 10-24 screws and M-LOK nuts for a secure, rigid attachment. Machined from 6061-T6511 aluminum and hard-coat anodized. Weighs 4.3 ounces. Features Really Right Stuff R-Lock dimples for positive engagement with RRS lever-release clamps while remaining compatible with every standard ARCA clamp.

This is the longest and most adjustment-capable aluminum ARCA rail in the 360 Precision lineup. For shooters who want the same 13-inch length with intentional forward weight, the Steel M-LOK ARCA Rail uses 1018 steel instead of aluminum.

Who should buy the 13” rail?

The 13-inch is built for shooters who change bipod position frequently and need the full range of adjustment their handguard can provide:

• You compete in PRS, NRL, or practical rifle and need to reposition your bipod between stages. Forward for prone settling, backward for barricade stability, anywhere in between for transitions. The 13-inch rail covers it all without running out of travel.
• You are building a dedicated precision rifle where the ARCA rail is a permanent fixture. The 13-inch commits the bottom of your handguard to ARCA. If you need room for a hand stop or foregrip, the 9-inch leaves more space.
• You shoot off a tripod. The balance point for tripod mounting is further back than a typical bipod position, and the 13-inch rail extends far enough rearward to reach it.
• You want full-length ARCA coverage at minimal weight. At 4.3 ounces, this rail weighs less than three loaded rounds of .308. The steel version adds intentional mass for prone stability. The aluminum version adds coverage without mass.

13-inch aluminum vs 13-inch steel: which one?

360 Precision makes two 13-inch M-LOK ARCA rails. Same length, same R-Lock dimples, same mounting system. Different materials for different purposes:

13″ Aluminum (this rail, $89, 4.3 oz): Lightweight. Adds ARCA capability with minimal impact on rifle balance. Best for general-purpose precision builds, hunting rifles, lightweight competition builds, and any setup where you want slide travel without adding forward weight.

13″ Steel ($179, 34.8 oz): Heavy. Adds intentional forward mass to help the rifle settle faster in prone and track more smoothly between targets. Best for dedicated prone-heavy competition builds, PRS gas guns, and bolt-action setups where added weight improves stability. Same concept as the weighted ARCA handguard on the Evolution Competition Rifle, applied to any M-LOK handguard.

If you are not sure which you need: start with aluminum. If you find yourself wanting the rifle to sit heavier in prone, switch to steel. If you find yourself wanting the rifle to move faster between positions, stay with aluminum.

What full-length ARCA coverage gives you that shorter rails do not

The practical difference between the 9-inch and 13-inch rail is not just four more inches of metal. It is where you can position your clamp:

On a 9-inch rail mounted to the front of a 15-inch handguard, your bipod clamp can slide within the forward 9 inches. That covers most prone and kneeling positions, which is why the 9-inch is the most popular length for general-purpose builds.

On a 13-inch rail, your clamp can slide from near the receiver all the way to the muzzle end of the handguard. That additional rearward travel matters in three specific situations:

Tripod shooting. The balance point for a tripod-mounted rifle is further back than for a bipod. A 9-inch rail mounted forward may not extend far enough rearward to reach the tripod balance point. The 13-inch rail covers it.

Reverse-loaded barricade positions. In PRS and practical rifle matches, some positions require loading the rifle backward against a barricade with the clamp positioned behind the magazine well. The 13-inch rail reaches those positions.

Adjusting balance with different magazine weights. A loaded 30-round magazine shifts the rifle’s balance point forward compared to a 20-round or 10-round magazine. Having full-length slide adjustment lets you compensate for that shift by moving the bipod clamp.

Compatibility

Mounts to: Any handguard or forend with M-LOK slots on the bottom (6 o’clock position). On a standard 15-inch AR-15 handguard, the 13-inch rail covers nearly the entire bottom. On shorter handguards (11.75 inches or less), verify that M-LOK slot spacing accommodates all five mounting screws before ordering.

Works with: Any ARCA-compatible bipod, tripod adapter, plate clamp, or barricade stop from Really Right Stuff, Area 419, MDT, Spartan Precision, Accu-Tac, and others.

Does not work with: Harris-style stud-mount bipods (requires an ARCA-to-stud adapter or an ARCA-native bipod). Picatinny-mount bipods require a Picatinny-to-ARCA adapter.

Hardware included: Five 10-24 screws and five M-LOK nuts.