Geissele REK H3 5.56mm NATO Reliability Enhancement Kit 05-492-H3

Geissele REK H3 5.56mm NATO Reliability Enhancement Kit 05-492-H3 was developed over the course of several years to solve reliability issues at their source rather than patching around them. The REK uses a 5.56mm full-mass, full-auto rated bolt carrier group with a properly torqued and staked, chrome-lined, nano-coated gas key, paired with a Super 42 Braided Wire Buffer Spring.

This Geissele REK H3 5.56 kit uses a cam pin precision machined from H13 tool steel, the same material used in medical instrumentation. Extended upper rails on the carrier improve stability and feeding dependability. The bolt itself is Geissele's exclusive Stressproof Bolt, made from Carpenter 158+ steel developed jointly between Geissele's engineers and Carpenter Steel metallurgists for a cleaner alloy with fewer impurities. Forged using the same process behind Geissele's upper and lower receivers, the bolt's grain structure gives it roughly five times the service life of a standard mil-spec bolt.

The carrier, cam pin, and bolt all receive Geissele's Reliability Enhancement Kit (REK) Nanoweapon coating, three years in development, delivering a surface hardness of 82 HRC along with strong resistance to abrasion, corrosion, and wear. The coating also rejects carbon buildup, making cleaning easier and reducing how much lubrication the weapon needs to run reliably.

Key Features:

• Full-mass, full-auto rated bolt carrier group
• Chrome-lined, nano-coated gas key, properly torqued and staked
• H13 tool steel cam pin
• Extended carrier rails for feeding reliability
• Stressproof Bolt, Carpenter 158+ steel
• Nanoweapon coating, 82 HRC surface hardness
• Super 42 Braided Wire Buffer Spring
• H3 buffer weight for a heavier recoil impulse than standard

These Geissele parts replace the weakest links in a standard bolt carrier group with components built to outlast them, in the heavier H3 buffer configuration.