GMB boring bar for SpeedTrim case trimmer

Custom made and perfect for converting .223/5,56 brass to .300 AAC Blackout.
When the carbide insert on this boring bar becomes dull, simply remove the GMB SpeedTrim case trimmer motor from the trimmer adapter, take out the M2.5x6 TORX screw, and rotate to a new cutting edge. Then, reinstall the motor and verify that the cut length hasn't changed. You can find more information on how to remove the trimmer from its adapter in the GMB SpeedTrim case trimmer user manual. To minimize vibrations, we recommend running the trimmer at close to maximum speed, which will also improve chip evacuation.