Radical Firearms 10.5" 5.56 NATO 1:7 Carbine Length M4 Barreled Upper - 10" Quad Rail

Manufactured by Radical Firearms
SKU: FU10.5-5.56M4-10FQR
MPN: FU10.5-5.56M4-10FQR
Manufactured by Radical Firearms
1 Review

Out of Stock

NOTE: Limit 1 per household. Quantities exceeding 1 will not allow checkout.



NOTE: This upper assembly has a barrel less than 16” in length. These uppers are intended for use in AR-15 pistols or legal short-barreled rifles. Other configurations may violate Federal law.

Does not include bolt carrier group or charging handle.

The Radical Firearms 10.5” 5.56 NATO M4 Barreled Upper Receiver is a law enforcement grade, drop-in solution for your next AR build. Crafted with quality materials and covered by Radical’s lifetime warranty, this MIL-SPEC upper receiver provides an outstanding solution for any budget. Arrives at your door with the hard work done! Finish the build with your favorite lower receiver, charging handle, bolt carrier group, and sights then head for the range!

The Radical Firearms First-Gen Quad Rail delivers a plethora of mounting options with its full length Picatinny rails. Its roomy 1.8” inside diameter can accommodate most suppressors on the market.

  • 10.5" 41V50 chrome moly vanadium steel M4 barrel with Melonite finish
  • Chambered in 5.56 NATO with 1:7 twist rate
  • 1/2x28 thread pitch A2 flash hider
  • 10" free float Radical Firearms Quad Rail
  • Made in the U.S.A. in Stafford, Texas!
See More


Barrel CoatingSalt Bath Nitride
Barrel ContourM4
Barrel Length10.5
Barrel LiningSalt Bath Nitride
Barrel Material4150 Chrome Moly Steel
BrandRadical Firearms
Caliber Gauge5.56 NATO
Gas System LengthCarbine
Gas System TypeDirect Impingement
Handguard10 in Quad Rail
Muzzle DeviceA2 Flash Hider
Thread Pattern1/2 X 28
Twist Rate1:7

WARNING: This Product can expose you to chemicals which is known to state of California to cause Cancer and Reproductive Harm. For more information, see www.p65warnings.ca.gov

Ratings & Reviews

1 review

  • 5 stars
  • 0 reviews
  • 3 stars
  • 0 reviews
  • 2 stars
  • 0 reviews
  • 1 star
  • 0 reviews

Not bad at all.

by -

Over all VERY impress with the upper. Hand guard it a bit wide for my taste but I replaced it with a slimmer one (Should have looked at their other one with a slimmer guard). But if you want a quad rail this is a well machines piece, with room for all your accessories. Barrel is well made and accurate for a 10.5 inch. For me the Barrel is the STAR component on this upper. Didn't see any lose or badly machined parts on this upper. Gas block is well placed and remains in place. Got it for $229, so I'm a happy camper. PA's rocks with service and delivery turn around!