Geissele Automatics MK8 Super Modular Rail — 13.5" M-LOK® Handguard | Desert Dirt Color (DDC) | Barrel Nut Wrench Sold Separately (GEI-02-243) | Gas Block Not Included | Model: 05-285S / 05285S | UPC: 854014005809
Upgrade your AR-15 with a professional-grade, duty-ready handguard engineered for rigidity, repeatable zero, and modern accessory mounting. The Geissele Automatics MK8 Super Modular Rail (SMR) — 13.5" delivers a rock-solid free-float interface, full-length 1913 Picatinny top rail, and generous M-LOK® real estate at 3, 6, and 9 o’clock. Finished in Geissele’s iconic Desert Dirt Color (DDC)—where shade variations and minor finish marks are normal due to the anodizing process—the MK8 combines battle-proven durability with a slim, ergonomic profile for fast manipulations and confident control.
Important: Barrel nut wrench sold separately (Geissele GEI-02-243). Gas block not included.
Why Choose the MK8 13.5" for Your Build
Bomb-Proof Lockup: Geissele’s SMR barrel-nut + two-bolt clamping system and anti-rotation tabs deliver an exceptionally stiff receiver/rail interface that helps maintain zero for lasers, irons, and aiming devices through heat and abuse.
Optimal 13.5" Length: The sweet spot for 14.5"–16" barrels (and many pinned/welded setups). Maximize reach for a modern C-clamp grip, push accessories farther forward, and retain suppressor/light clearance.
Top Rail + M-LOK Everywhere: Continuous Picatinny up top for BUIS and accessory bridges, with M-LOK® along the sides and bottom for lights, QD sockets, hand stops, vertical grips, and rail covers.
Slim, Contoured Ergonomics: Ovalized cross-section and venting promote natural hand placement and heat dissipation on high-round-count days.
DDC That Works Hard: Desert Dirt Color is tough and distinct; finish shade variation and small cosmetic marks are expected and add to its hard-use aesthetic.
Proudly Made in the USA: Geissele materials, machining, and QC are trusted by professionals and enthusiasts alike.
Key Features at a Glance
Product: Geissele MK8 Super Modular Rail, AR-15 free-float handguard
Length: 13.5 inches
Interfaces: Full-length 1913 Picatinny top rail + M-LOK® at 3/6/9 o’clock
Mounting System: Geissele SMR barrel nut with two-bolt clamp (wrench GEI-02-243 required; sold separately)
Anti-Rotation: Integrated tabs for secure, aligned installation
Finish/Color: DDC — Desert Dirt Color (shade variations/finish marks normal)
Includes: Handguard, SMR barrel nut & mounting hardware (per package)
Not Included: Barrel nut wrench (GEI-02-243), gas block, gas tube, sights, or other accessories
Model / UPC: 05-285S / 05285S | 854014005809
Compatibility & Fit Notes
Platform: AR-15 pattern upper receivers.
Best Pairings: Common with mid-length and carbine gas systems on 14.5"–16" barrels; verify gas block clearance with your profile.
Gas Block: Use a low-profile gas block (not included).
Suppressor/Device Clearance: Slim body works with many mounts and cans; always confirm ODs and spacing.
Installation: Follow Geissele’s torque specs and instructions; professional armorer installation recommended. Use the GEI-02-243 wrench for the SMR barrel nut.
Real-World Performance Advantages
Laser/BUIS Stability: The MK8’s stiffness helps hold zero for IR pointers and iron sights through barricade pressure and heat cycles.
Modern Light Placement: M-LOK along multiple clock positions lets you mount a white/IR light and switch exactly where your support hand wants it—no awkward adapters.
Free-Float Accuracy: Isolating the barrel from handguard pressure supports consistent POI and precision—valuable for duty and match rifles alike.
Control & Speed: The 13.5" length extends your support-hand leverage for faster transitions, better recoil management, and steadier positional shooting.
Ideal Use Cases
Duty/Defense Carbines: Rugged lockup for lights, QD sling points, BUIS, and night-vision accessories.
Competition & Training: Light, rigid front end that rewards fast target transitions and stable holds.
Suppressed Setups: Plenty of space for tuck-adjacent mounting while maintaining gas block/suppressor clearance.
What’s in the Box
Geissele MK8 Super Modular Rail — 13.5" (DDC)
Geissele SMR barrel nut and mounting hardware (per package)
Printed installation notes (as provided by manufacturer)
You May Also Need (Sold Separately)
Geissele Barrel Nut Wrench — GEI-02-243 (required for installation)
Low-profile gas block & gas tube appropriate to your barrel/gas system
M-LOK accessories (QD sockets, rail covers, hand stop/foregrip, light mounts)
Armorer tools (upper receiver fixture, torque wrench, thread prep/locker)
DDC Finish Disclosure — Read Before You Buy
Geissele’s Desert Dirt Color anodizing produces a unique patina; color tone, shade variation, and minor cosmetic imperfections are normal and vary from part to part—even within the same batch. These characteristics are not defects and contribute to the MK8’s distinctive, hard-use look.
Care & Maintenance
Wipe down with a soft cloth after range sessions; avoid harsh abrasives on anodized finishes.
Periodically check mounting bolts and M-LOK fasteners for torque (follow accessory manufacturer specs).
Inspect for carbon/heat discoloration near the gas block area—cosmetic only, typical of high use.
Frequently Asked Questions
Q: Is the barrel nut included?
A: Yes, the SMR barrel nut is included. The barrel nut wrench (GEI-02-243) is sold separately.
Q: Will this fit any AR-15 upper?
A: It’s designed for AR-15 pattern uppers. Confirm gas block height and barrel profile for clearance within the 13.5" handguard.
Q: Why does my DDC look different than photos?
A: DDC shade variation is expected. Differences in hue and subtle marks result from the anodizing process.
Q: Does it include a gas block or sights?
A: No. You’ll need a low-profile gas block, sights, and any other accessories separately.
Q: Can I DIY the install?
A: Experienced builders can; otherwise, we recommend a professional armorer to ensure proper torque, timing, and alignment.
SEO Highlights (For Shoppers)
Geissele Automatics MK8 13.5" Super Modular Rail DDC
M-LOK handguard with full-length Picatinny top rail & anti-rotation tabs
SMR barrel nut included; barrel nut wrench GEI-02-243 sold separately
Gas block not included; free-float design improves accuracy and accessory stability
Model 05-285S / 05285S, UPC 854014005809 — Desert Dirt Color with normal shade variations
Lock in a premium, free-float front end that’s built for hard use and precise accessory placement. The Geissele MK8 Super Modular Rail — 13.5" (DDC) gives your AR-15 the rigidity, ergonomics, and M-LOK flexibility trusted on duty rifles and elite builds across the country.
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