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Radical Firearms 5.56 Pistol RPR M-LOK SBA3 Brace - 10.5"

Manufactured by Radical Firearms
SKU: FP10.5-5.56M4-10RPR-SBA3
MPN: FP10.5-5.56M4-10RPR-SBA3
Manufactured by Radical Firearms
5 Reviews

In Stock

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

Standard orders received before 4:00pm CST will ship out the same day. FFL orders will ship within 3 business days as long as we have the information for the transfer destination.

Items that are regulated by the ATF have restrictions and requirements: 
•Your entire order will ship only to a Federal Firearm License holder.
•Current processing time is approximately 14 to 16 days.
•Please contact your local FFL prior to placing your order to ensure they are still accepting transfers. Due to Covid-19 many are no longer open
•A copy of your order/invoice as well as the current FFL license for your local dealer must be emailed to ffl@primaryarms.com.



The Radical Firearms 5.56 AR Pistol has been upgraded for 2019 with the popular SB-Tactical SBA3 5 position adjustable arm brace. This stabilizing brace is extremely durable and rigid with plenty of adjustment for different arm lengths and features a QD sling swivel slot for carrying or added stability when shooting off hand. It also allows for a proper cheek weld giving you a variety of ways to shoot your AR pistol. This model comes with a 10.5” barrel machined from 4140 Chrome Moly steel with a Melonite finish and a 1:7 twist rate. A popular twist rate for heavier 62 grain projectiles combined with a carbine length gas system make for an accurate and reliable system. M4 feed ramps help to angle the cartridges into the chamber and help to prevent FTF malfunctions. The Radical Firearms 5.56 pistol paired with the SBA3 stabilizing brace make this gun extremely fun at the range.

  • 10.5” barrel chambered in 5.56 NATO
  • Machined from 4140 steel with Melonite finish
  • M4 barrel profile
  • 1:7 twist rate
  • Carbine length gas system
  • .750” low profile gas block
  • A2 style flash hider
  • Forged 7075-T6 aluminum receivers
  • Type III anodized
  • 10” RPR free float handguard
  • M-LOK compatible
  • Mil-Spec parts kit
  • Mission First Tactical Ergo pistol grip
  • SBA3 pistol arm brace

This 5.56 NATO pistol features an upper and lower receiver forged out of 7075-T6 aluminum and a type III anodized finish for added durability and corrosion resistance. It is assembled with mostly Mil-Spec parts; however, it features a Mission First Tactical Ergonomic pistol grip. Also included is the Radical Firearms 10” RPR M-LOK handguard. This handguard comes with a few features of its own like an extremely durable barrel nut that free floats the barrel for better accuracy and indexes with the upper receiver to prevent it from rotating loose. It features lightening cuts to reduce weight and a continuous picatinny top rail for iron sights and other accessories. The slim and minimal design is extremely comfortable and lightweight to use without sacrificing the ability to set your gun up exactly the way that you want.

Radical Firearms offers law enforcement grade hardware. Crafted with quality materials and covered by their lifetime warranty, Radical Firearms is an outstanding choice for any budget.
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Barrel CoatingMelonite
Barrel ContourM4
Barrel Length10.5
Barrel LiningMelonite
Barrel Material4140 Chrome Moly Steel
BrandRadical Firearms
Caliber Gauge5.56 NATO
Frame SizeAR Pistol
Gas System LengthCarbine
Gas System TypeDirect Impingement
Handguard10 in M-LOK Rail
Thread Pattern1/2 X 28
Twist Rate1:7
Weight5.47 lbs

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

5 reviews

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I love mine


I'll email 10.5inch barrell5.56runs like a clock.

Awesome gun


Amazing gun for the price can't beat it anywhere

Satisfied Owner


Great firearm. Went to my lease and broke in the barrel with open sights at 25 meters. Getting 1moa group. Went to 50 and still tight groups. Also ordered the Midwest Blast Diverter and it really helps. Great customer service and quick shipment.

Good to go


Took it to the range to brake it in and worked very well ! Lil fire breather !

Pure magic


I purchased the Primary Arms/Radical Firearms special pistol back in January and I can't tell you how pleased and satisfied I am ! Not only from the quality of this piece but the quality of Primary Arms and their staff !!! Van and everyone else at Primary I've encountered are stand up great people. Made my purchase and experience all well worth it. Even though it took sometime which is totally understandable they were the best in handling everything about my experience ! Thank You guys and gals I will continue to support and deal with Primary Arms always !!! This Radical Firearms AR pistol is a great addition to my AR arsenal and I couldn't be happier :D Thanks PA