Surefire Scout, Modlite, Cloud Defensive REIN: Which Mount Pattern Fits Each Light

Here's the answer most people are looking for: the Surefire Scout footprint is the industry standard, and almost every major weapon light uses it. Modlite (OKW, PLH, PLHv2), Cloud Defensive REIN, Streamlight ProTac Rail Mount and HL-X, Olight Odin, and Arisaka's entire light line all use the same two-screw Scout mounting pattern. That means a single Scout-compatible mount fits nearly all of them. You don't need a different mount for each brand.

The Scout footprint works through two threaded M4 holes on the bottom of the light body, spaced 0.85 inches apart. Any mount labeled "Scout-compatible" or "Scout pattern" bolts to those two holes. Surefire introduced this footprint in 2006, and because it works so well, the rest of the industry adopted it rather than inventing competing standards.

But there are two important exceptions and one trap that catches buyers off guard, and that's what the rest of this guide covers. The mount pattern is nearly universal; the switch and tailcap ecosystem is not. Get this wrong and you'll buy a light and a switch that physically won't work together.

Method Dynamics builds Scout-pattern light mounts for AR-15 platforms, and this guide explains exactly which lights fit which mounts and where the compatibility actually breaks.

What the Scout Footprint Actually Is

The Surefire Scout mounting footprint is a simple, robust interface: two M4 threaded holes on the underside of the light body, spaced 0.85 inches (about 21.6mm) apart. The mount has two matching through-holes. You use the screws provided with the mount to bolt the light body directly to the mount, which then attaches to your handguard via M-LOK, Picatinny, or KeyMod.

The genius of this system is its simplicity. There's no proprietary clamp, no brand-specific locking ring, no special interface. Just two screws into two threaded holes. That simplicity is why it spread across the industry.

A manufacturer building a new weapon light in 2026 has every incentive to use the Scout footprint because it instantly makes their light compatible with the enormous existing ecosystem of Scout mounts from Arisaka, Unity Tactical, Haley Strategic, Reptilia, KDG, and dozens of others.

The result: the mount you choose is driven by the position and style you want (offset, inline, top-rail), not by which brand of light you own. This is the opposite of the suppressor mount world, where proprietary interfaces still fragment the market.

The Master Compatibility Table

Light	Uses Scout Footprint?	Body Diameter	Switch Ecosystem
Surefire M300 series	Yes (originator)	1.00 in	Surefire SR07, ST07, tailcaps
Surefire M600 series	Yes (originator)	1.00 in	Surefire SR07, ST07, tailcaps
Surefire M640DFT Pro	Yes (Pro swivel body)	1.00 in	Surefire (Pro-specific mounts)
Modlite OKW (all versions)	Yes	1.00 in body	Surefire-compatible switches
Modlite PLH / PLHv2	Yes	1.00 in body	Surefire-compatible switches
Cloud Defensive REIN / REIN 3.0	Yes	~1.00 in	Proprietary connector
Cloud Defensive REIN Micro	Yes	~1.00 in	Proprietary connector
Streamlight ProTac Rail Mount 1 / 2	Yes	1.00 in	Streamlight (fragile, see below)
Streamlight ProTac HL-X (non-laser)	Yes	1.00 in	Streamlight or Surefire adapter
Olight Odin	Yes (mostly)	1.00 in	Proprietary Odin mount for some models
Arisaka 300 / 600 / 18650	Yes	1.00 in	Surefire-compatible switches

The pattern is clear: nearly every light uses the Scout footprint for the mount, so the physical mounting is a solved problem. Where compatibility fragments is in the switch and tailcap ecosystem, which we cover next.

The Switch Compatibility Trap

This is the single most important thing in this guide, and it's the detail that competing compatibility charts skip. The Scout footprint standardizes how the light attaches to the mount. It does not standardize how the light's remote switch or tailcap connects to the light body.

Surefire and Modlite share a switch ecosystem. Modlite deliberately built their lights to accept Surefire-compatible tailcaps and remote switches. A Surefire SR07 tape switch works on a Modlite body. A Modlite ModButton works on a Surefire body. This cross-compatibility is intentional and one of the reasons Modlite became so popular: you can mix and match bodies, heads, tailcaps, and switches across both brands.

Cloud Defensive uses a proprietary connector. This is the trap. The Cloud Defensive REIN uses the Scout footprint for mounting, so it fits any Scout mount. But its switch and tailcap connector is proprietary. You cannot use a Surefire SR07 or a Modlite ModButton on a REIN. If you buy a REIN expecting to run your existing Surefire switch, you'll be disappointed. The REIN comes with its own switch, and you're locked into Cloud Defensive's switch ecosystem.

Streamlight switches are Scout-mountable but fragile. The Streamlight ProTac HL-X uses the Scout footprint and can accept its own tape switch, but Streamlight's tape switches have a known reliability weakness. The rotary connector can loosen under recoil. The common fix is to run the HL-X with its standard tailcap, or buy an Arisaka adapter that lets you use bombproof Surefire Scout switches instead.

The practical takeaway: choose your switch ecosystem before you buy the light. If you already own Surefire or Modlite switches, stay in that ecosystem (Surefire, Modlite, or Arisaka bodies). If you buy Cloud Defensive, accept that you're committing to their proprietary switch. If you buy Streamlight, plan to either run the tailcap or add a Surefire-compatible switch adapter.

The Two Real Exceptions

Beyond the switch trap, there are two lights where the mount compatibility itself has a caveat.

Olight Odin. Many Olight Odin models ship with a proprietary M-LOK mount rather than a Scout-footprint mount. Some Odin variants do use the Scout footprint, but others use Olight's own quick-detach interface. If you own an Odin and want to use a standard Scout mount, verify your specific model has the Scout footprint before buying an aftermarket mount. This is the one mainstream light where you can't assume Scout compatibility.

Surefire Scout Pro (swivel body) models. The newer Surefire Scout Pro lights (M640DFT Pro and similar) use a swivel body that requires Pro-specific mounts. A standard Scout mount will physically attach, but you lose the swivel functionality the Pro body was designed around. If you bought a Pro model specifically for the swivel feature, you need a Pro-compatible mount (like the Arisaka Inline Scout Pro Mount) to use it as intended.

For everything else on the compatibility table, a standard Scout-pattern mount works without caveat.

Choosing Your Mount Style

Since the footprint is universal, your real decision is mount style and position. There are three common configurations, and we cover the full placement logic in our offset light mount guide and weapon light position guide. Here's the quick version:

Inline mounts hold the light parallel to the rail, directly on the M-LOK or Picatinny surface. Best for top-rail (12 o'clock) or side (3/9 o'clock) mounting. Many inline mounts designed for 45-degree handguard flats let you adjust the light's exact position by a fraction of an inch to clear iron sights or other accessories.

Offset mounts hold the light at a 45-degree angle, placing the bezel at roughly the 1:30 or 10:30 clock position. This is the most popular modern configuration because it eliminates barrel shadow, sits low against the handguard, and puts the tailcap under your support thumb in a C-clamp grip. Flip the mount and the light goes to the 4:30 or 6:30 position for niche setups.

Lightbar / extension mounts push the light further forward down the rail. Useful for suppressor-ready builds where you want the light near the end of a can to reduce suppressor shadow, and for shorter handguards where rail space is tight.

The Method Dynamics light mount collection covers inline and offset Scout-pattern mounts in both M-LOK and Picatinny interfaces.

Installation and Torque Specs

Because all Scout-pattern mounts use the same two-screw interface, the installation is consistent across brands. The specs that matter:

Light body to mount screws: Torque to about 20 inch-pounds with a medium-strength thread locker (Loctite 222 or 243). These are the two M4 screws that bolt the light body to the mount. Over-torquing these can strip the light body's threaded holes, which is expensive to fix.

Mount to handguard (M-LOK): Torque the M-LOK T-nut hardware to about 30 inch-pounds. Use a torque driver, not hand pressure. This is the connection that shifts under recoil if it's under-torqued.

Driver requirement: Most Scout mounts use a T20 Torx or IP20 TorxPlus driver for the M-LOK hardware. Removing the stock Picatinny rail adapter from a Surefire Scout light typically requires a T9 Torx driver. Have both on hand before you start.

Re-check after break-in: Both connections should be re-checked after the first 100 to 200 rounds. Initial torque can settle slightly as the components seat, and a quick re-torque catches anything that moved before it becomes a problem.

Common Buyer Mistakes

1. Assuming Cloud Defensive REIN takes Surefire switches. It doesn't. The REIN uses the Scout mounting footprint but a proprietary switch connector. If switch cross-compatibility matters to you, this is the one major light to avoid, or accept the proprietary switch.

2. Buying a Scout mount for an Olight Odin without checking the model. Some Odins use Olight's proprietary mount, not the Scout footprint. Verify before buying an aftermarket Scout mount.

3. Running a Streamlight tape switch and expecting it to survive. The Streamlight tape switch's rotary connector is the weak point. Run the tailcap or adapt to a Surefire switch.

4. Over-torquing the light body screws. The two M4 screws that hold the light to the mount go to about 20 inch-pounds, not "as tight as it goes." Stripping the light body's threads is a common, avoidable, and costly mistake.

5. Mounting the light without confirming handguard slot position. A 45-degree offset mount needs an M-LOK slot at the right position on your handguard. Confirm your handguard supports the offset position you want. Our free-float handguard line includes offset slot positions on select models for exactly this reason.

6. Buying a Pro-body Surefire and a standard mount. If you bought a Scout Pro for its swivel feature, a standard mount defeats the purpose. Get a Pro-specific mount.

What This Means for Your Build

The short version: the Surefire Scout footprint is the universal weapon light mounting standard, and a single Scout-pattern mount fits Surefire, Modlite, Streamlight, Arisaka, and Cloud Defensive REIN lights.

The mount you choose is driven by style and position (inline, offset, or extension), not by light brand. The one real gotcha is switch compatibility: Surefire and Modlite share a switch ecosystem, Cloud Defensive is proprietary, and Streamlight tape switches are best replaced with Surefire-compatible ones.

If you're building a complete setup, pick your light and switch ecosystem first, then choose a Scout-pattern mount in the position that suits your grip. The Method Dynamics light mount line covers the common Scout-pattern configurations, all CNC-machined in the USA. Pair it with a matched free-float handguard that has the offset slot positions you need, and your light setup is done.

Method Dynamics is a US firearms accessory manufacturer combining 40+ years of engineering, design, and manufacturing experience from top-tier industry brands. Every Method Dynamics product is designed, prototyped, manufactured, and tested in the USA. Browse our Scout-pattern light mount collection or pair it with a matched free-float handguard to complete your build.