A quick and easy method to install choke tubes using a lathe (can be done by hand, however, a lathe gives superior results). Tap and reamer are precision ground from high speed steel and use the same interchangeable pilot bushings. Reamer has an enhanced end relief that provides a faster cut. Pilot bushings are available in diameter increments of .001", and are 2" long for accurate bore alignment. Factory instructions are included. Note: Read and understand the installation requirements before proceeding. For best results, remove any existing choke with the Angle Blade Expanding Choke Reamer prior to using the Loon Lake Choke reamer. Click here for proper installation requiremen Mfg: Manson Precision SPECS: 12 Gauge has .795"-44 tpi. Accepts standard (not thinwall) Tru-Choke tubes. 20 gauge has .675"-44 tpi.