-Buffer Tube Milling File (intended to shave down the best of the AR-10 Buffer tube so that the charging deal with can very clear on some upper/reduce mixtures) The GG3 creates lots of aluminum chips and you do not want stray chips ending up at the rear of the spindle. https://ghost-gunner-349905.tinyblogging.com/ghost-gunner-no-further-a-mystery-76518085