The Sanders Armory 8.5″ 300 AAC Blackout Match Grade 416R Stainless Steel Light Weight contour barrel features 5R rifling with a 1:8 Twist rate, in addition to a Nitride Barrel Extension and a PISTOL-Length Gas system.
Expect nothing less than professional grade 300 AAC Backout barrels from Sanders Armory.
- Brand: Sanders Armory
- Barrel Caliber: 300 AAC Blackout
- Barrel Length: 8.5″ Inches
- Twist Rate: 1:8 Twist
- Rifling process: 5R Button Rifled
- Barrel Concentricity held to .002
- Material: 416R Stainless Steel
- Finish: Polished Stainless Steel
- Barrel inside Finish: Polished Stainless Steel
- Profile: Light Weight Contour
- Gas System Length: Pistol Length Gas Tube
- Diameter Gas Block: .750 Gas Block
- Dimple Gas Block: Yes
- Crown Thread Pattern: 5/8 x 24 Thread Pitch
- Barrel Crown: Single Point Cut Polished 11-degree Target Crown
- Extension: M4 Nitride Coated
- Feed Ramps: M4 cut Barrel extension
- Weight: 1 Lbs 1oz.
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.