Geissele AR15 Reaction Rod

The Geissele AR15 Reaction Rod (5.56/.223) is a tool designed to support upper receiver assembly and maintenance for AR15-pattern rifles. Intended for use with a bench vise, the rod interfaces with the barrel extension using integrated splines to help stabilize the upper receiver during procedures such as barrel installation, removal, and handguard or gas system work. This design allows the user to secure the assembly without clamping directly onto the receiver.

By directing torque forces through the barrel extension rather than the aluminum receiver, the Reaction Rod is intended to reduce stress on critical components during installation tasks. The rod is machined from 4140 chrome moly steel and finished to a precise diameter for consistent fitment. It is compatible with standard AR15 upper receivers chambered in 5.56/.223, including platforms such as the HK MR556.

Specifications

• Compatibility: AR15 / 5.56 NATO / .223 Rem upper receivers
• Application: Barrel installation, removal, and upper receiver maintenance
• Mounting: Designed for use with a bench vise
• Interface: Integrated splines engage barrel extension
• Material: 4140 chrome moly steel
• Construction: Precision ground for consistent fitment
• Function: Transfers torque through barrel extension
• Use Case: Gunsmithing and armorer tasks
• Additional Compatibility: HK MR556 upper receivers