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Questions & Answers
Are slims needed to properly time barrel nut? Expert Answer

Yes, you would need to shim the barrel nut for proper timing.

by Ethan C., Gear Expert, October 18, 2019
do i just need to use a normal barrel nut wrench or do i need to buy a different one or does this come with its own proprietary wrench? Expert Answer

The barrel nut uses a standard barrel nut wrench.

by Jonathan D., Gear Expert, June 14, 2018
Customer Reviews
Helpful Positive Review
Radical Forearms M-lok by Ryan, March 21, 2021
This is a good rail. It’s very slim and light weight. I would recommend it to a friend. I just wish their finish was a little more resistant to oil. It kind of soaks it in a little. And leaves a dark spot.
1/1 found this helpful
Helpful Positive Review
Radical Arms FCR Hand Guard by Pebblebeachkid, December 20, 2017
I was looking for this particular hand guard in 15" to replace the 12" that came on my rifle. Optics Planet had it substantialy cheaper than anyone else and had it in stock. It shipped in 3 days and arrived in 10 days via FedEx surepost. I'm happy wi...
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1/1 found this helpful
Helpful Positive Review
Fantastic Rail by James, Verified Owner, January 20, 2018
I really like this rail, A LOT. It's a slim rail, but fit easily over my low profile gas block. It comes with a steel barrel nut. I really like that the barrel nut is smaller in diameter so the gas tube runs over it, not through it. Saves a littl...
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1/1 found this helpful
Helpful Negative Review
Value priced handguard by Tom Bates, Verified Owner, October 7, 2019
This a great price compared to other hands guards costing two or three time the price of this one. This is a decent hand guard. The finish was not the best ,but acceptable. After I sprayed it down with w-40 and wiped it clean it looked a lot better. ...
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1/1 found this helpful
Most Recent Reviews
Picture is not what you actually get by Zach M, Verified Owner, March 11, 2020
Either False Advertisement or They shipped the wrong hand-guard... I got not only a blemished part but its also the Wrong style... The finish is pretty bad... The hand guard I got has the mounting bolts at the bottom and is clamp style not the style ...
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1/2 found this helpful
Most Recent Reviews
Perfect fit by David Frazer, Verified Owner, August 1, 2019
Found this item, on an awesome sale, for my 9mm carbine build. Perfect fit for an awesome look. Well made with MLOK on the entire length. Came with the barrel nut. Although I don't have to worry about indexing, the barrel nut fits flush and the rail ...
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Read All 10 Reviews
Color:
Black
Finish:
Type III Class 2 Hard-Coat Anodized
Gun Make:
AR Platform
Gun Model:
AR-15
Gun Type:
Rifle
Handguard Length:
7 in
Gun Rail:
M-LOK
Condition:
Open Box, Dealer DMO
Included Accessories:
Standard
Quantity:
1

Code: 2CS-HZ-RFFCRS-7FCR-DMO

MPN: R-7FCR-DMO

Product No Longer Available

Product Info for Radical Firearms M-LOK Slim Rail System (FCR)

Save weight and add massive utility to your weapon with the Radical Firearms M-LOK Slim Rail System (FCR). These AR Handguards & Forends made by Radical Firearms feature a Type III Class 2 Hard-coat Anodized Finish for superior resistance to corrosion and abrasion. The Radical Firearms M-LOK Free-Float Rail System (FCR) features a seamless Mil-Spec 1913 top Picatinny rail for the attachment of optics, lights, lasers and other accessories that will improve your aim and performance in the field. Customize your gun with this one-piece Radical Firearms M-LOK Ultralight Rail System (FCR) to expand your tactical capabilities.image

Features of Radical Firearms M-LOK Slim Rail System (FCR):

  • 1 piece free float design
  • Ultra Light and Rigid Design
  • 4140v Steel Barrel nut
  • Seamless top rail
  • Mil-Spec 1913 Top Picatinny Rail
  • M-lok Design to accept any accessory
  • Type III Class 2 Hard-coat Anodized Finish

Package Contents:

  • Radical Firearms M-LOK Slim Rail System (FCR)
  • Handguard
  • Barrel Nut
  • Mounting Screws

Gun Barrels

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Gun Parts and Accessories

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Gunsmithing Tools & Accessories

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Magazine and Accessories

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Gun Triggers

1–15 / 15
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Gun Sights

1–19 / 19
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Gun Stocks

1–17 / 17
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Mounts, Rings and Accessories

1–18 / 18
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Related Products to Radical Firearms M-LOK Slim Rail System (FCR)

Radical Firearms M-LOK Slim Rail System (FCR) Unavailable & Discontinued Models

List of Unorderable Models

  • Open Box, Dealer Demo, Radical Firearms M-LOK Slim Rail; FCR 7 inch, Black, 7FCR , MPN: R-7FCR-DMO , Code: 2CS-HZ-RFFCRS-7FCR-DMO
  • USED Radical Firearms M-LOK Slim Rail, FCR 7 inch, Black, 7FCR, EDEMO1, Used, Condition Fair, Installed/Mounted , MPN: R-7FCR-EDEMO1 , Code: 2CS-HZ-RFFCRS-7FCR-EDEMO-IN-D
  • Radical Firearms M-LOK Slim Rail; FCR 7 inch, Black, 7FCR , MPN: R-7FCR , Code: 2CS-HZ-RFFCRS-7FCR
  • Radical Firearms M-LOK Slim Rail; FCR 10 inch, Black, 10FCR , MPN: R-10FCR , Code: 2CS-HZ-RFFCRS-10FCR
  • Radical Firearms M-LOK Slim Rail; FCR 12 inch, Black, 12FCR , MPN: R-12FCR , UPC: 816903021796 , Code: 2CS-HZ-RFFCRS-12FCR
  • Radical Firearms M-LOK Slim Rail; FCR 15 inch, Black, 15FCR , MPN: R-15FCR , Code: 2CS-HZ-RFFCRS-15FCR
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Last updated 2026-09-28 UTC.