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Marines Seek Range and Precision Enhancement for EFSS

More reach and lethality for the Corps' 120 mm rifled towed mortar system

Marine Corps representatives will soon be receiving industry proposals for a new munition system designed to extend the range and precision fires requirements for the service’s Expeditionary Fire Support System (EFSS). Dubbed Precision Extended Range Munition (PERM) system, the new munition will significantly expand the tactical flexibility of Marine Corps expeditionary elements.

The EFSS is a close support, all weather, quick response indirect fire system. The main weapon is the M327 120 mm rifled towed mortar (RTM), which currently has an effective range of approximately 8 kilometers.

As envisioned, the PERM “All Up Round” (AUR) will consist of a projectile and propelling charge, with the complete AUR stored and transported within the PERM container.

EFSS bore

Close-up photo of the rifled bore of a 120 mm EFSS. Photo by Scott R. Gourley

In outlining PERM performance specifications, Marine Corps planners have identified a number of both “threshold” and “objective” requirements for a new 120 mm ammunition option for the RTM.

In terms of ranges, for example, planners call for a minimum range not to exceed a threshold range of 12 kilometers with an objective range desire of 8 kilometers. Maximum ranges are identified as not less than a threshold of 16 kilometers with an objective maximum range of 20 kilometers.

Accuracy goals call for a circular error probable (CEP) of less than 20 meters (threshold) and 10 meters (objective) “with respect to target GPS coordinates at all operational ranges.”

Identified target set criteria for PERM include: suppressing, neutralizing and destroying motorized targets; suppressing and neutralizing light armored targets; destroying dismounted personnel targets; and destroying soft command and control targets.

Warhead fuzing options will include threshold options of height of burst (HOB) and point detonating (PD) with the addition of a “delay” option as an identified objective.

Performance specifications note that “HOB shall be the primary fuze mode,” adding, “HOB should be selected to meet lethality requirements.”

Those lethality requirements for the new PERM round against that target set are identified in comparison to the M1101 High Explosive warhead currently used with the EFSS to provide both fragmentation and blast effects against personnel and material targets. Specifically, based on warhead arrival parameters, planners call for the PERM warhead lethal area to be 80 percent (threshold) to 100 percent (objective) of the lethal area for the M1101.

It is anticipated that the PERM Engineering and Manufacturing Development program will include the possibility of multiple awards, with a statement of work including requirements associated with the development, manufacture and demonstration of 42 PERM rounds.


Scott Gourley is a former U.S. Army officer and the author of more than 1,500...