Manganese Phosphate Barrel Finish on entire barrel
Bolt machined from Mil-Spec Carpenter No. 158® steel
HPT Bolt (High Pressure Tested/ Proof)
MPI Bolt (Magnetic Particle Inspected)
Shot Peened Bolt
Chrome Lined Carrier (AUTO)
Chrome Lined Gas Key
Gas Key Hardened to USGI Specifications
Grade 8 Hardened Fasteners Key
Staked Per Mil-Spec
Tool Steel Extractor
Black Extractor Insert
Receivers Machined from Aluminum Forgings 7075-T6
Receivers Hardcoat Anodized per MIL-A-8625F, Type III, Class 2
Staked M4 Lock Nut
USGI H Buffer (1 USGI Tungsten, 2 Steel)
Low Shelf for RDIAS installation
Low Shelf for Accuwedge use
Fire Controls marked SAFE and SEMI
Caliber Dictionary
The Below Information Has Been Provided From Our Gun Caliber Dictionary And Is Meant For Informational Purposes Only. It Is Not Intended to Describe The Unique Specifications For This Ammunition.
The 5.56X45mm NATO cartridge was designed by James Sullivan, a member of Eugene Stoner's engineering team that developed both the M16 rifle and its original cartridge. The 5.56X45mm NATO was adopted by the U.S. military in 1964 and by NATO in 1980. With bullet diameter of .224-inch, the original M193 military cartridge used a 55-grain bullet at 3250 fps; the current M855A1 cartridge, developed by FN, uses a 62.5-grain bullet at 3020 fps, offering greater range and better penetration. The civilian version of the 5.56X45mm is 223 Remington; the cartridges are dimensionally identical but military chamber dimensions and specifications for military brass are different. It is considered safe to use 223 Remington ammo in a 5.56X45MM NATO chamber, but not a good idea to use 5.56X45mm ammo in a rifle specifically chambered for the 223 Remington. Although the stopping power of .22-caliber bullets remains controversial the 5.56X45mm has served well in now multiple generations of M16 rifles. — Craig Boddington
