This was done mainly for cost-saving and availability reasons since the Armed Forces of the Philippines are actively engaged in counter-insurgency and internal security operations, especially against the Moro Islamic Liberation Front (MILF), Abu Sayyaf Group and occasionally, the communist New People's Army.

The deployment of the MSSR also allowed the Philippine Marine Corps to retire its M1903 Springfield, M1C Garand and M14 rifles from active service.

[6][3] The first-generation MSSR used either factory 5.56mm NATO 62-grain SS109 ball ammunition or 69-grain Federal Match Gold Medal boattail hollowpoint (BTHP) cartridges.

[2] The first generation MSSR was deployed in 1996 as an M16A1 with a Tasco variable 3-9 x 40 mm rubber-coated scope on a DPMS Tri-mount atop the carry handle.

[7] The second generation MSSR was created by removing the forward portion of the carry handle and attaching the Tri-mount directly to the top of the upper receiver.

[2] The fourth generation rifles, introduced in 2016, feature a Leupold Mark 4 LR/T M3 scope mounted on a Leupold mount, an 18-inch cold hammer-forged Daniel Defense barrel, a JP match trigger, a Harris swivel bi-pod, a tactical charging handle latch, ambidextrous fire controls, an extended trigger guard and a Magpul Precision-Adjustable stock.

[8] Night vision and regular daytime scopes can be mounted on the rifle via a Picatinny rail on top of the upper receiver.

The new rifle will feature an 18" free-floating bull barrel with a 1 in 7" twist, a standard A2 flash suppressor, a flattop upper receiver with a Picatinny rail, provisions for a bipod and semi and select fire.

It features a railed upper receiver, a mid-length gas system, a Daniel Defense 16-inch cold-hammer forged barrel, a Daniel Defense free-floating railed handguard, a 4x32 Trijicon Advanced Combat Optic, a Magpul STR buttstock, a Hogue foregrip with a cleaning kit, and a cerakote finish.