Sanders Armory 18″ Match Grade 5.56 NATO Stainless Steel AR15/M16 BILLET SIDE CHARGE Upper Assembly with MPI Tested Mil Spec .223/5.56/300 Blackout Nitride BCG and Bolt with Phosphate Extractor and 5R Rifling. This Premium AR15/M16 BILLET SIDE CHARGE Upper Assembly with MPI Tested Mil Spec .223/5.56/300 Blackout Nitride BCG and Bolt with Phosphate Extractor and side charge handle features a 18″ Match Grade 5.56 NATO 416R Stainless Steel Tapered HBAR Barrel with 1:8 Twist and 5R Rifling. It includes a Rifle Length Stainless Steel Gas Tube, a Low Profile .750 Gas Block with Nitride Finish, Standard AR15 Charging Handle, YOUR CHOICE of a Sanders Armory Slim Line, Free Float 15″ or 16.5″ KEYMOD Handguard, and YOUR CHOICE OF MUZZLE BRAKE between the 1/2 x 28 Stainless Steel or Nitride Tapered Fat-Comp or A2 Flash Hider.
Shipped fully assembled unless requested otherwise.
The Sanders Armory 18″ Match Grade 5.56 NATO Stainless Steel AR15/M16 BILLET SIDE CHARGE Upper Assembly with MPI Tested Mil Spec .223/5.56/300 Blackout Nitride BCG Package includes:
- AR15/M16 BILLET SIDE CHARGE Upper Receiver
- 18″ Match Grade 5.56 NATO 416R Stainless Steel 5R Tapered HBAR Barrel with 1:8 Twist
- YOUR CHOICE OF Sanders Armory 12″ or 15″ Ultra Slim Free Float KEYMOD Handguard
- Low Profile .750 Gas Block with Nitride Finish
- Stainless Steel Rifle Length Gas Tube
- YOUR CHOICE OF AR-15 Stainless Steel or Nitride Flash Hider or Tapered Fat Comp
- Standard AR15 Mil Spec Charging Handle
- MPI Tested Mil Spec .223/5.56 NATO/300 Blackout Nitride BCG and Bolt with Phosphate extractor and side charge handle.
What is 5R Rifling?
Retired Army man, Barrett “Boots” Obermeyer developed 5R rifling as a gunsmith in his families store and holds a High Master Classification in both high-power rifle disciplines, is a Distinguished Rifleman and has won numerous shooting awards at both state and national levels. The best definition comes from “Boots” himself …
“5R is the form of rifling I developed for use in most target barrels and in many sporting barrels,” he explained. “These barrels have 5 grooves, and the lands have angular sides. I have observed that bullet jackets will deform such that they remain closer to the R-form lands than they will to the sharp-edged lands present in conventional-style rifling. This reduces powder fouling at the corner of the grooves. The angled form of the lands also helps to reduce jacket failures in quick-twist barrels.”
The diagram above of rifling profiles shows the difference between traditional rifling (top) and 5R rifling (bottom). Note that the edges of 5R are not square (they don’t cut into bullet jacket as much) and that with 5R, the lands are opposite of grooves while with traditional rifling, lands are opposite lands and grooves are opposite grooves.
NO shipping to District of Columbia (Washington, D.C.); Massachusetts; Connecticut; Chicago, Cook County, Deerfield, Highland Park or Aurora Illinois; New Jersey; New York; Puerto Rico; Hawaii; or Canada. NO international shipping all must be within the 48 Contiguous United States. NO APO/PPO/FPO’s.