The SR-15 E3 MOD 2 series� 5.56mm NATO barrel is manufactured for military grade durability, and is free-floated inside a URX4 M-LOK handguard. An improved E3 round-lug bolt design both enhances function and increases bolt life far beyond the industry standard. The 5.56mm 3-Prong Flash Eliminator interferes with propellant gas combustion forward of the muzzle to significantly reduce flash signature, will not ring upon firing or when struck, and is compatible with the Knight�s line of 5.56mm QDC Signature Reduction Devices.