HK416 / MR556 Barrels / Gas Blocks

Nefarious Arms Gas Piston for HK G36, HK SL8, HK416 and HK MR556 A great spare, upgrade, or replacement part for your HK. Includes 3 piston rings for a complete drop in replacement part. TiN coated for corrosion resistance.  Compatible...

HK MR556, HK 416 Barrel Nut Or Socket For Barrel - Aluminum A must have repair and replacement part for removal or when you have any work done to your barrel as the barrel nut may become damaged in the removal and installation processes. Made in the USA...

HK G36, HK SL8, HK 416, & HK MR556 Gas Piston Complete assembly with 3X rings installed and nitrided black. Counts as one US-made compliant part for your SL8-G36 style conversion. This is one of the best parts to use on the conversion as it is one of...

H&K HK MR556 A4 Gas Block - Complete Factory HK MR556 A4 adjustable gas block ideal for switching between suppressed and unsuppressed firing.   Compatible With: HK MR556 A4 Nefarious Arms A5 barrels NOT compatible with MR556 A1 without...

Nefarious Arms HK 416 Gas Block Assembly Tool A Nefarious Arms creation for those that like to service or replace their 416 gas block. This assembly tool will effortlessly help you assemble or disassemble your 416 gas block by simply aligning the two...

Nefarious Arms HK 416 Barrel Installation and Multi Tool HK416 multitool patterned off a genuine HK 416 wrench with added features.  Use with a traditional 1/2″ torque wrench or the plug-and-socket style torque wrench that utilizes the ball...

Heckler and Koch HK German 10.4" Barrel Non-Vented Gas Block Complete Factory HK NON-VENTED 10.4" gas block. Compatible With: HK416 10.4" uppers HK MR556 to 10.4" conversions

Titanium HK MR556, HK 416 Barrel Nut Or Socket For Barrel A must have repair and replacement part for removal or when you have any work done to your barrel as the barrel nut may become damaged in the removal and installation processes. Made in the USA...

H&K HK MR556 A4/HK416A5 Barrel Nut This precision-machined steel barrel nut is designed specifically for H&K’s MR556 A4 and HK416A5 rifles. It secures the barrel and supports the proprietary HK free-floating handguard system, offering...

HKP Barrel Bore Cleaning Brush - 5.56 / .223 HKP barrel bore cleaning brush for 5.56 and .223 caliber HK firearms. Designed to help remove fouling and buildup from the bore during routine maintenance, this brush is a practical cleaning tool for...

Heckler and Koch 11" Barrel for HK416A5, MR556 A4, MR556 A5 Factory German 11" HK416A5, MR556 barrel. Cold hammer-forged and built to HK’s standard for durability, accuracy, and service life. The 1:7 twist rate stabilizes a wide range of 5.56 NATO...

Nefarious Arms HK MR556 A3/416 A5 Barrel Nut Whether replacing a barrel nut or sourcing the best parts for your build, the Nefarious MR556/416 barrel nut is an excellent option.  Meticulously crafted in the US to the highest quality standards...