Radical Firearms 10.5" 300 BLK 1:8 Pistol Length HBAR Barreled Upper - 10" Primary Arms Exclusive M-LOK Rail

Manufactured by Radical Firearms
SKU: PABU10.5-3003
MPN: PABU10.5-300
Manufactured by Radical Firearms
3 Reviews

Out of Stock

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



The Radical Firearms 10.5” 300 BLK HBAR Barreled Upper 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. Complete this build with your favorite lower receiver, bolt carrier group, charging handle, and sights, then head for the range!

Includes the Radical Firearms/Primary Arms Exclusive M-LOK Handguard. Crafted from 6063-T6 aluminum and hardcoat anodized a deep black, this tough, durable rail offer a slim, modular profile. Large cooling holes along the rail reduce weight and aid in rapid cooling. Take advantage of M-LOK positions along the 3, 6, and 9 o’clock of the rail for all your favorite gear. An uninterrupted M1913 Picatinny top rail offers space to mount optics, sights, and other accessories with ease.

NOTE: This upper receiver has a barrel that is less than 16” in length and is intended for use in AR pistol or legal short-barreled rifle builds. Other configurations may violate Federal law.

Does not include bolt carrier group or charging handle.

  • 10.5" 41V50 chrome moly vanadium steel HBAR barrel with Melonite finish
  • Chambered in 300 BLK with 1:8 twist rate
  • 5/8x24 A2 flash hider
  • 10" free float Radical Firearms/ Primary Arms Exclusive M-LOK Rail
  • Gen 3 rail mounting system
  • Made in the U.S.A. in Stafford, Texas!
See More


AssemblyBarreled Assemblies
Barrel ContourHBAR
Barrel Length10.5
Barrel Material41V50 Chrome Moly Vanadium Steel
BrandRadical Firearms
Caliber Gauge300 Blackout
Gas System LengthPistol
Gas System TypeDirect Impingement
Handguard10 in Radical Firearms/Primary Arms Exclusive M-LOK Rail
Muzzle DeviceA2 Flash Hider
Twist Rate1:8

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

3 reviews

  • 4 stars
  • 0 reviews
  • 3 stars
  • 0 reviews
  • 2 stars
  • 0 reviews

Isn’t worth the gamble

by -

Initially I was impressed by the overall appearance of the upper.
<br> However, since it’s first time to the range, it’s been short stroking at least once every 10 rounds. I’ve tried swapping in different BCGs, ammo from various manufactures (all supersonic), and different magazines..all to no avail. Guess I’ll have to throw some money at it for it to be reliable.
<br>Should have purchased another Palmetto State upper instead.

Quality 300 Upper!


Got this bad boy on sale a few weeks ago. Was an amazing investment. Finally got my build done and this barrel is a laser beam! With my UTG circle dot sight, I was having one hole groups at 25 yards no problem. Most accurate AR15 I own. Fired 150 rounds with zero malfunctions. Used 125 grain magtech and S&B 200 grain subsonic ammo. Both functioned flawlessly and hit POA with almost boring accuracy.

Great Upper!!!

by -

Great upper. I put this on a build and have never had an issue with feeding and it is very accurate. Glad I made this purchase.