The Sanders Armory 13″ Match Grade 6.5 Grendel Type II Stainless Steel SIDE CHARGE LIGHTWEIGHT Upper Assembly with BCG Package includes an Sanders Armory AR15 / M16 Mil Spec BILLET SIDE CHARGE Upper Receiver with MPI Tested Mil Spec 6.5 Grendel Type II Nitride BCG and Bolt with Phosphate extractor, 13″ Match Grade 6.5 Grendel Stainless Steel Tapered HBAR Barrel with with 1:8 Twist and 5R Rifling, Carbine Length Stainless Steel Gas Tube, Sanders Armory 15″ Free Float LIGHTWEIGHT Skeletonized MLOK Handguard, Low Profile .750 Gas Block with Melonite Finish, 5/8 x 24 Melonite Flash Can. Shipped fully assembled unless requested otherwise.
The Sanders Armory 13″ Match Grade 6.5 Grendel Type II Stainless Steel SIDE CHARGE LIGHT WEIGHT Upper Assembly with BCG Package includes:
- Sanders Armory AR15 / M16 Mil Spec BILLET SIDE CHARGE Upper Receiver with MPI Tested Mil Spec 6.5 Grendel Type II Nitride BCG and Bolt with Phosphate extractor
- 13″ 6.5 Grendel Type II Match Grade Stainless Steel Tapered HBAR Barrel with 1:8 Twist and 5R Rifling
- Sanders Armory 15″ Free Float LIGHTWEIGHT Skeletonized MLOK Handguard
- Low Profile .750 Gas Block with Melonite Finish
- Stainless Steel Carbine Length Gas Tube
- AR-10 Melonite Flash Can with 5/8 x 24 Thread
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.
“Boots” himself provides the Best Definition …
“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.
We do not ship 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; Alaska or Canada. No international shipping, all must be within the 48 Contiguous United States. No APO/PPO/FPO’s.