The 360 Precision Low Profile ARCA Rail 5.1″ is a compact, ultra-lightweight ARCA dovetail rail that mounts directly to any M-LOK handguard. It weighs 1.6 ounces and gives your rifle full compatibility with ARCA-standard bipods, tripods, plate adapters, and quick-release clamps without adding meaningful weight or changing the balance of your setup.

The rail is machined from 6061-T6511 aluminum and hard-coat anodized. It bolts to your handguard with three 10-24 screws and three M-LOK nuts (all included). The underside of the dovetail features Really Right Stuff R-Lock dimples, which provide positive anti-slip engagement when paired with RRS lever-release clamps like the ARC-LR.

If you have been running a Pic rail segment or a Harris bipod adapter on your M-LOK forend and want to move to the ARCA ecosystem, this is the simplest, lightest way to get there.

Who should buy this rail?

• Hunters and lightweight-build shooters who want ARCA bipod and tripod mounting without adding weight. At 1.6 ounces, you will not notice it on the rifle.
• NRL22 and rimfire precision competitors running compact setups where a full-length rail would be overkill.
• Anyone with an M-LOK handguard who wants to try ARCA accessories before committing to a longer, heavier 9″ or 13″ rail.

How does the 5.1″ compare to the 9″ and 13″ versions?

All three Low Profile ARCA Rails use the same aluminum, the same anodized finish, and the same R-Lock dimples. The only differences are length, weight, and how many mounting screws they use:

• 5.1″ (this one): 1.6 oz, 3 screws. Fixed-position bipod mounting. No meaningful slide adjustment. Lightest option. Best for short handguards, lightweight builds, and setups where the bipod stays in one spot.
• 9″ (also available): 2.8 oz, 3 screws. Several inches of slide travel. Enough to move a bipod clamp forward or backward for different shooting positions (prone vs kneeling vs barricade). The most popular length. Best for general-purpose and precision AR-15 builds.
• 13″ (also available): 4.3 oz, 5 screws. Full-length coverage for maximum slide range. Allows bipod placement anywhere from the receiver end to the muzzle end of the handguard. Best for dedicated precision builds and competition setups where position flexibility matters most.

Start with the 5.1″ if you are not sure you need the extra length. You can always move up later.

Frequently Asked Questions

Will this fit my handguard?

If your handguard has M-LOK slots on the bottom, yes. The rail mounts using standard M-LOK hardware and fits any M-LOK forend regardless of manufacturer. It does not require a specific brand or proprietary mounting system.

What is R-Lock and do I need it?

R-Lock is a dimple pattern developed by Really Right Stuff that creates positive mechanical engagement between the ARCA rail and compatible RRS clamps. It prevents the clamp from sliding under recoil, which matters most on heavy-recoiling rifles or when shooting from unstable positions. If you use an RRS ARC-LR or similar R-Lock clamp, you get the benefit automatically. If you use a non-RRS ARCA clamp, the rail still works perfectly. The dimples do not interfere with standard ARCA dovetail engagement.

Can I mount a Harris-style bipod to this rail?

Not directly. Harris bipods use a stud-mount or Picatinny adapter, not the ARCA dovetail. To use this rail, you would need an ARCA-compatible bipod (like an Accu-Tac, Area 419, or Atlas with ARCA feet) or an ARCA clamp with a bipod stud adapter.

Is this strong enough for a precision rifle?

Yes. The 6061-T6511 aluminum is the same alloy used in most premium handguards, and the three-screw M-LOK mount distributes load across a wide area. For lightweight precision rifles and rimfire platforms, the 5.1″ rail handles bipod and tripod loads without issue. For heavy precision rifles over 15 lbs or aggressive barricade use with heavy clamp pressure, the 9″ or 13″ versions provide additional contact area and rigidity.