I recently sent my Glock 19 in to have the slide milled for a RMR and cocking serrations. The work ATEi performed was outstanding. Not only was the work flawless it was performed in an extremely timely manner. I had previously sent a Glock 17 to a competitor for RMR milling and waited 7 months before getting my pistol back. ATEi kept to their published return time and I had my pistol in time to use at class I was signed up for. In the future I will be using ATEi for my gun smithing needs.