The NSR Pro is our first and probably only lightweight build.  Coming in at just 54OZ (3lb 6oz) this is a true lightweight upper that still performs to a very high standard and doesn't shoot like a standard lightweight upper. Its excellent shooting performance comes from two factors, a lightweight BCG (8.9 OZ Complete) and an adjustable gas key from Rubber City Armory. The combination of low reciprocating mass and fine adjustments on the gas key means the NSR Pro is a very fast, very flat shooting upper receiver. Now this is not what I consider to be a duty or extreme use build as the lightened BCG and pencil barrel will not hold up as well to abuse and excessive thermal cycling. The point of this build is to maintain the highest level of performance in as light of a package as possible. Every component is still backed by our no questions asked lifetime warranty, and yes the first rebarrel is still free. 
 
*Alternate Muzzle Devices Available Upon Request At Dealer Cost - Includes FREE P&W With KAK Flash Hider*
 
The Basics
 
14.7" Ballistic Advantage Pencil Profile 5.56 1:7 Twist 4150 CMV Barrel, KAK 13" 7-Sided Mlock Handguard, RTB Lightweight BCG, Rubber City Armory Adjustable Gas Key, Aero Precision Slick Upper, & Breek Warhammer Charging handle
 
Lapped Upper Receiver, Bedded Barrel, Every component is hand fitted and tested prior to assembly, test firing, and ultimately shipping. 
 
The Specifics
 
Barrel:
Manufacturer - Ballistic Advantage
Length/Chamber - 14.7" 5.56
Twist - 1:7 
Material - 4150 CMV
Profile - Pencil
Gas System - Mid-Length
Finish - Nitride
Thread Pitch - 1/2x28
Gas Port - .082
Weight - 21 oz
1st Rebarrel - FREE
 
I tested with several loads and was able to get good (1 MOA) performance out of HSM 77gr and Nosler 77gr ammo. I also was able to get this upper consistently out to 700 yards. 
 
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 - RTB
Bolt Material - 9310 Alloy
Carrier Material - 8620 Alloy
Gas Key Material - 4140 Alloy (Rubber City Armory Adjustable Gas Key)
Profile - Lightweight
Finish - Nitride/NIB
Gas Key Screws - Grade 8
Forward Assist Cuts
Mil-Spec Firing Pin (Hard Chrome Coated)
Viton O-Ring Enhanced Extraction

 
Handguard:
Manufacturer - KAK Wedge Lock
Length - 13"
Material - 6061 T6 Aluminum
Finish - Hard Coat Black Anodization
Mounting Platform - Mlock
Barrel Nut - Steel
 
Barrel nut torqued to 50 FT-lbs
Handguard screws torqued to 60 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 - Aero Slick Side
Material - 7075 T6 Aluminum
Machined from Forged Aluminum
Finish - Type 3 Hardcoat Anodized Black
Standard Dust Cover
M4 Feed Ramps
T-Marked, if you care...
 
Charging Handle:
Manufacturer: Breek Arms Warhammer (ambi + gas busting)
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 - .625"
Attachment Method - 2x Set Screws
Not Adjustable
 
Set screws are torqued to 30 IN-lbs and have Rockset applied for Ultimate security.
 
*Please contact me before attempting removal of the Gas Block. These are not meant to be tampered with. 

 
Gas Tube:
Length - Mid Length
Material - Stainless Steel
 
*** Any flash hider/ muzzle brake on the market can be substituted at dealer cost on your upper ***
 
Flash Hider:
Type - A2 Extended
Manufacturer - KAK
Thread Pitch - 1/2x28
Caliber - .223/5.56