Surefire Scout M640DF - Arkayne

Surefire Scout M640DF


Lead Time on this product: 1 - 10 Business Days

The Surefire M640DF is a solid contender in the world of weapon mounted illumination devices. Lights. We meant lights, but wanted to say it..fancier.

What makes the M640DF such a capable light?

Surefire in general is regarded as one of the giants in the weaponlight world. They have been around for a long time, and their lights have a consistently proven track record. The Scout M640DF is a compact light that has solid white light performance. The new swivel mounting system allows quick mounting to either MLOK or Picatinny rail sections. The light can be rotated into an ideal position for streamlined function on modern fighting rifles.

A quick rundown of some of the specs of the M640DF:
  • Dual Fuel Capability: Run either 2X CR123A or ONE 18650 Battery
  • Up to 1500 Lumens with 18650 Battery, 1200 Lumens with CR123A Batteries
  • Up to 16,000 Candela with 18650, 12,800 Candela with 2X CR123A batteries
  • Versatile Low Profile mount keeps the light close to your rail
  • Lightweight yet rugged construction

Our team has had great experiences with this light. For anyone looking for surefire durability and adaptability in a white light, the M640DF might be a good fit.

Out of stock


The M640DF is a proven, high performance weapon mountable white light.

In a world where candela is king, the Surefire lights land in the middle of the pack. While they may not have the highest candela output, they do have a solid reputation and very usable beam pattern. Another side benefit of the surefire lights is the vast array of aftermarket support for the lights. This equates to more mounting options and more accessories for end users.

Where does the Surefire M640DF Shine:

The Scout M640DF is a solid contender. The newer style mount keeps the light close to your rail, yet allows a great amount of adjustment for various platforms. Included in the packaging is a picatinny and MLOK mounting solution. Changing the mount is easy with the included Allen wrench. The 640DF is lightweight and has a small form factor. Durability is second to none in our experiences and users should expect high performance and a long service life.

Adaptability and expandability is key.

Aftermarket support and internal support are key attributes for surefire. A host of different switches and tail caps are available for the 640DF. The one downside is the light comes only with a push button tail cap. This simply means end users who desire a pressure pad activation will need to purchase a tail cap and pressure pad separately. You can find those products HERE.

For customers looking for a solid, no-frills white light that has great lumen output, solid light throw with a nice beam pattern, the M640DF might be a good fit.


Spectrum of Light

Visible White Light


Black Anodized

Lumen Output

1500 (18650), 1200 (CR123A)

Candela Output

16,000 (18650), 12800 (CR123A)


Z68 Push Button Switch


Picatinny & MLOK


Approximately 5.5oz

Bezel Diameter



1.) How does the Surefire M640DF stack up against ModLite and Cloud Defensive?  

When it comes to quality, there are many options on the market. This is a great thing for the community. Surefire does not necessarily have the best candela or lumen output, but the M640DF does have a very usable beam pattern with a solid amount of throw. Compared the the REIN, MCH, or Modlites, the Surefire does not put out as intense of a light. The M640DF will not throw light as far as either of these. The REIN is an absurdly bright lighting system, but a downside is lack of interchangeability with pressure pads and tail caps.

2.) Who should consider the M640DF weapon light? 

We avoid blanket recommendations without first understanding the end goal. That being said, if you love surefire, already have tail caps and switches, or want consistency on your builds, getting the M640DF might make a ton of sense. Surefire is also regarded as some of the highest quality lights on the market. If your primary concern is a quality light with expansive aftermarket support, the 640DF may be the light for you.

3.) What is included with the M640DF?  

Inside the retail packaging is the light body, Picatinny adapter, MLOK adapter, 18650 battery, and Allen wrench tool for mounting and adjustment.

4.) What is the battery life like on the 640DF? 

We have never tested total run time, but we have used the 640DF often enough to know that it is comparable to other lighting options on the market. With more potent light output comes shorter battery life. The M640DF has an advertised run time of 1.5 hours with an 18650 battery, 1.25 hours with CR123A.

5.) What about a warranty?

Contact Surefire if any problems exist with your light.

6.) Are these stocked or drop shipped? 

We stock what is shown on our site here in our warehouse. These are NOT drop shipped. We hold the inventory, we ship at time of order.

7.) Are Surefire lights still worth it in the world of other great companies? 

We think so. Are they for everyone? Probably not. The surefire reputation of quality and performance should be noted. For many people, they buy a surefire for the durability and reliability. For others, it’s in the name. We run many different lighting solutions on our rifles. We are happy with the M640DF for its service life, compact fit and function, and the reputation it carries.


The M640DF does NOT include a pressure switch or tail cap for pressure switch. additional accessories can be purchased HERE.

Customer Reviews
Rated 0 out of 5
Based on 0 review(s)
Write a review

There are no reviews yet.

A note about our current lead times:

Arkayne is a RAPIDLY growing brand. Because of that, some of our suppliers have a hard time keeping up. There are occasions where WE experience lead times from our partners, and we do our absolute best to post the lead times at the top of our product pages. BEFORE PURCHASING: look at the lead time on the product pages. If you have ANY questions regarding lead times,  Email: and we will send you our closest ETA. We know you are pumped to get your gear, and we will process your order as fast as possible. We aren’t Amazon, we are a small US owned business that gives a rip about getting you equipped. We will get you your gear ASAP. See you in the darkness.