THE HERO PRIMER


Primers are key components in tank cartridges— ensuring they function reliably is critical.


ammunition and systems HERO-compli- ant. On Dec. 1, 2010, DOD released the latest version of the standard, MIL-STD- 464C, “Department of Defense Interface Standard: Electromagnetic Environmen- tal Effects Requirements for Systems,” that “establishes electromagnetic envi- ronmental effects (E3) requirements and verification criteria for airborne, sea, space, and ground systems, including associated ordnance.” Te intent was to ensure that all systems and ordnance for those systems could be “sufficiently shielded or otherwise so protected that all electrically initiated devices contained by the item are immune to adverse safety or reliability effects when the item is employed in the radio frequency environment delineated in the standard.” Te objective for PM MAS then became to develop a HERO-safe primer for all large caliber (120 mm and 105 mm) tank cartridges.


THE HERO PRIMER After much work between Picatinny engi- neer design teams and industry partners, there are now two acceptable configura- tions of the HERO primer—the one-piece and two-piece designs (Figures 4 and 5).


Table 1 identifies the differences between the legacy thick-wall, one-piece and two- piece primers. Te manufacturing process of both variants of HERO primer reduces the level of hands-on assembly required, thereby reducing production costs. Te HERO configurations also eliminate the need for lacquer plugs and black powder.


Te comparison table shows the reduction in the number of critical defects from the


TEST ROUND


Soldiers assigned to 4th Infantry Division test the XM-1147 Advanced Multipurpose round in September at Yuma Proving Grounds, Arizona. (U.S. Army photo illustration courtesy of Maj. Michael Brabner)


FIGURE 4


The one-piece design is one of only two acceptable configurations of the HERO primer. (Image courtesy of the author)


FIGURE 5


The two-piece HERO primer reduces the level of hands-on assembly required, thereby reducing production costs. (Image courtesy of the author)


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Army AL&T Magazine Winter 2022


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