CQB Pro - 10.5" 5.56 Complete Upper Receiver - Pinned Gas Block

The CQB Pro is as the name implies our shortest, most handy upper in our Pro lineup. This 10.5" upper is designed to be as tough and reliable as it can be within the short length envelope. Rosco Bloodline Barrels provide the accuracy and soft shooting performance you should expect. The BCGs are the top of line NIB Toolcraft BCGs, some of the best on the market. For the rail we went with one of the strongest in the market, The Geissele MK4. The CQB was not designed to be the lightest upper, but the strongest and most durable for the hardest use cases you can think of. 


***Each Upper is Laser Engraved/Serialized 1-15 by Rosco at The Factory***


*Alternate Muzzle Devices Available Upon Request After Purchase*


The Basics


10.5" Rosco Bloodline 5.56 1:7 Twist 4150 CMV Barrel, Geissele 9.3"MK4 Handguard, Toolcraft NiB BCG, Mil-Spec Upper, Breek Warhammer Charging handle & SI Cloak Flash Hider


Pinned Gas Block, Lapped Upper Receiver, Bedded Barrel, Every component is hand fitted and tested prior to assembly, test firing, and ultimately shipping. 


The Specifics



Manufacturer - Rosco

Length/Chamber - 10.5" 5.56

Twist - 1:7 Twist

Material - 4150 CMV

Profile - M4

Gas System - Carbine-Length

Finish - Nitride

Thread Pitch - 1/2x28

Gas Port - .073

Weight - 19.25 oz


*Pinned Gas Block*

1st Rebarrel - FREE


All NFA/ATF Rules Apply


Barrel nut is sequentially torqued down to 50 FT-lbs. Starting at 25, then 35, and then finally 50 FT-lbs to ensure proper mating of the threads. 


Barrel is also bedded to the upper receiver with an expanding/hardening compound to ensure perfect fit and reliable accuracy. 


If you legit burn out a barrel, like 10,000 -25,000 rounds, and the barrel becomes inaccurate I will rebarrel it for you for free. Good luck.



Bolt Carrier Group:

Manufacturer - Toolcraft

Bolt Material - 9310 Alloy

Carrier Material - 8620 Alloy

Gas Key Material - 4130 Alloy

Profile - Full Auto

Finish - Nickel Boron

Gas Key Screws - Grade 8 (torqued and staked to Mil-Spec)

Forward Assist Cuts

Mil-Spec Firing Pin (Hard Chrome Coated)

Viton O-Ring Enhanced Extraction




Manufacturer - Geissele

Length - 9.3"

Material - 6061 T6 Aluminum

Finish - Hard Coat Black Anodization

Mounting Platform - Mlock/Quad

Barrel Nut - Geissele Proprietary (does not require timing)


Barrel nut torqued to 50 FT-lbs

Handguard screws torqued to 96 IN-lbs with blue Loctite


We apply a Permatex Anti-Seize solution to the receiver extension before installing the barrel nut to ensure they do not lock up over many years of hard use. 



Upper Receiver:

Manufacturer - 17 Design

Material - 7075 T6 Aluminum

Machined from Forged Aluminum

Finish - Type 3 Hardcoat Anodized Black

Standard Forward Assist

Standard Dust Cover

M4 Feed Ramps

NOT T-Marked, if you care...


Charging Handle:

Manufacturer: Breek Arms

Material: 7075 T6 Aluminum

Machined from Forged High Strength 7075 Aluminum

Finish - Type 3 Hardcoat Anodized


Gas Block:

Material - 4140 Steel

Style - Low Profile

Size - .750"

Attachment Method - 2x Set Screws + Steel Roll Pin

Not Adjustable

Dimpled to barrel


Set screws are torqued to 25 IN-lbs and have High-Temp threadlocker applied for extra security.


*Please contact before attempting removal of the Gas Block. These are not meant to be tampered with. 



Gas Tube:

Length - Carbine

Material - Stainless Steel

Finish - Black Nitride


Flash Hider:

Manufacturer - Strike Industries

Cloak - 4-Prong Flash Hider (expect some minor tuning fork ringing)

Material - 4140Steel

Thread Pitch - 1/2x28

Caliber - .223/5.56


The Build Process:


Every upper is assembled by me, one at a time. Every piece is hand fit, barrels to the uppers, gas blocks to the barrels, gas tubes to the blocks, handguards, roll pins. If something doesn't fit properly and securely, I don't put it together. What that means is that you get an upper where every component fits together like a glove for a rock solid build that won't fall apart or tear itself asunder during hard use.


On top of that we use the proper threadlocker on the appropriate parts. We use blue loctite on the handguard screws and then torque them to 60 IN-LBS. On the gas block screws we torque them to 25 IN-LBS then use a red high temp threadlocker (#272) to ensure the gas block never shifts. #272 threadlocker holds its strength up to 450 degrees VS. the 300 degrees of standard loctite. 


We don't use the high temp threadlocker on the flash hider or the barrel nut. We can if you ask us to, I don't have a problem with that. But, it is not needed. 50 FT-lbs on the barrel nut is more than enough and the flash hider is timed with a crush washer and can be easily swapped out for your favorite device if you so desire. 

CQB Pro - 10.5" 5.56 Complete Upper Receiver - Pinned Gas Block

  • Our stated policy is to not accept returns, but if you accidently ordered the wrong item or there was a mistake or if you have any issue at all send us an email (listed in the "contact us" section) and we will work it out.