AR15/M4 Reaction Block

Geissele AR15/M4 Reaction Block - Mil-Spec Buffer Tube Only

The Geissele Reaction Block® was developed to simplify the assembly of the lower receiver. Once the gunsmith has installed the buffer tube, the lower receiver can then be slid into the Reaction Block at the 12, 3, 6, and 9 o’clock positions. This allows the gunsmith to rotate the lower receiver within the block in 90° increments by simply loosening the included nylon screws, removing the lower receiver, and sliding it back in at the desired orientation. The Reaction Block provides an ultra-stable platform for performing a range of operations on the lower receiver and makes installing the buffer mount nut quick and easy. All of this is possible while the gunsmith has both hands free to work, saving both time and frustration.