A couple years ago, URR posted this introduction to the Marine Corps combat use of the rifled 120mm mortar Expeditionary Fire Support System. It’s light weight (relative to other fire support options) has led to its adoption as the primary direct support indirect fire weapon in Marine artillery regiments.
One major potential shortcoming of the EFSS is its short maximum range of about 8500 meters. Given that shortcoming, the Marines began the development of PERM, or the Precision Extended Range Munition.
Not only does the use of a guided munition increase the first round accuracy of a shot, the fins allow the trajectory to be shaped to dramatically alter the path of the round, greatly extending the range, to a quite respectable 17,000 meters or so.
Last month, Raytheon, the developer, fired four PERMs in successful tests. An additional 42 rounds of test firing are due this year. If successful, the PERM should begin to show up on the caissons of the EFSS shortly thereafter.