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Questions & Answers
Is there a recommended gas block best used with the Geissele 15in Super Modular Rail MK4 M-LOK Expert Answer

I recommend using the Geissele Super Gas Block with the Geissele 15in Super Modular Rail MK4 M-LOK. However, we currently do not have this gas block available.

by Hunter, Gear Expert, October 5, 2022
Will this Fit a Ruger AR 556 new to Mlok use to the old pictanny rail Expert Answer

The Geissele 15in M-LOK Super Modular Rail MK4 will fit Mil-Spec AR15's. So it will work with a Ruger AR556, but if you have a Ruger AR556 with an A2 front sight gas block that will need to be removed and replaced with a low profile gas block.

by Hunter, Gear Expert, April 5, 2022
Customer Reviews
Helpful Positive Review Tier 1 Quality �� by Stinky, February 25, 2024
I recently scored this for my AR 20” rifle swapping it out replacing older style YHM free floater . The Geissele barrel nut is well machined and thought out, i recommend getting their tool for the few bucks to make ur life easier. The handguard is ...
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1/1 found this helpful
Helpful Positive Review Geissele 15inch mk4 rail. by Jake, July 23, 2016
After looking at a lot of rails for both my 300 blackout and 556 build i decided on this rail do to the fact that i can retain correct barrel nut torque without having to take the rail off and on and the barrel nut off and on to get the rails to matc...
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4/4 found this helpful
Helpful Positive Review Very nice product. by Napalmjerry, March 23, 2018
The fit and finish is top notch. The rail is nice and wide so those of you with large hands will love this. The only thing I can complain about is the variation of color between individual rails, but they are very upfront about this so I can’t fault ...
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1/1 found this helpful
Helpful Positive Review Fit and finish superb by ASK, September 2, 2017
Awesome. Beautiful. Love the color. Fits more secure than any rail. Super as are all Geissle products. Easy, secure install!!!!!!!! Con ............ PRICE but you get what you pay for. Only comparable is Faxon carbon fiber, also expensive!!!
1/1 found this helpful
Helpful Positive Review Fantastic rail by MattP, Verified Owner, May 3, 2017
Let's get this out of the way first: Yes, it's expensive. However, for the price you are also getting a very nice low-pro gas block, so if you can manage a coupon and then back out the cost of the GB, you're closer to $200 than $300, and that's easie...
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1/1 found this helpful
Helpful Positive Review 15in Geissele Mk4 by Niko, July 29, 2017
This is an absolutely beautiful piece of machinery. Quality on every inch of this Geissele artwork. It is very easy to install (only about 15 minutes). The fit of the handguard over the barrel nut is immaculate.
1/1 found this helpful
Read All 12 Reviews
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Help support American manufacturing! Marked models of this product have gone through rigorous review and been certified by the manufacturer as Made in the USA.

Product Info for Geissele 15in Super Modular Rail MK4 M-LOK

The Super Modular Rail MK4 M-LOK from Geissele is an ultra-lightweight option for full-size AR builds. At 15 inches in length, these rails are purpose-built and feature integrarted Picatinny rail sections at the front of the rail in the 3, 6, and 9 o'clock positions. The free-floating design also lends itself to efficient barrel venting, ensuring heat can dissipate swiftly after you fire.image

The MK4 Super Modular Rail also has M-LOK connections along the rails and in the upper 45 quadrants so that you can mount a variety of accessories to customize your weapon to your exact needs. The modular nature and versatility of the MK4 is what makes it stand out from the crowd, giving you options for tactical, functional, and sport shooting upgrades.

The Super Modular Rail MK4 also features the Geissele's proprietary 2.25-inch long barrel nut, which is larger and stronger than other varieties. The extra length increases the nut's surface contact where the rail interfaces with the receiver, creating a platform that is straight and true. With the extra rigidity, you can maintain your accuracy and zero-in your optics reliably.

WARNING: California`s Proposition 65

Specifications for Geissele 15in Super Modular Rail MK4 M-LOK:

Manufacturer: Geissele
Finish: Type III Hardcoat Anodized
Gun Type: Rifle
Handguard Length: 15 in
Handguard Type: Free-Float
Gun Rail: Picatinny
Weight: 12.8 oz
Condition: New
Included Accessories: Standard
Inner Diameter: 1.35 in
Outer Diameter: 2.11 in
Height: 2.4 in
Mount Type: M-LOK
Country of Origin: USA
Quantity: 1

Features of Geissele 15 inch Super Modular Rail MK4:

  • Picatinny Rails
  • M-LOK Connections
  • 2.25-inch Barrel Nut
  • Free-floating Handguard
  • Anodized Finish

Package Contents:

  • Geissele 15in M-LOK Super Modular Rail MK4

Geissele 15in Super Modular Rail MK4 M-LOK Orderable Models

List of Orderable Models

Geissele 15in Super Modular Rail MK4 M-LOK, Black, 05-315B , MPN: 05-315B , UPC: 854014005731 , Code: 1TO-HZ-15MK4-05-315B
Geissele 15in Super Modular Rail MK4 M-LOK, DDC, 05-315S , MPN: 05-315S , UPC: 854014005748 , Code: 1TO-HZ-15MK4-05-315S

Proposition 65 Warning for California Consumers

For more information go to www.p65warnings.ca.gov

Notification

WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

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