Special Operations Peculiar Modification (SOPMOD) Kit

The Special Operations Peculiar Modification Kit (SOPMOD) Program managed at the Naval Surface Warfare Center, Crane Division (NSWC Crane) conducts Research and Development directed toward ordnance and electronics, processes, systems, subsystems and components in support of special operation warfighters. For Ordnance, the SOPMOD programs primary technical areas include Small Arms, Ordnance, and Optical fire control systems. The Electronics area includes Displays and Peripherals, Night Vision/Electro-Optics and Laser based fire control systems. The mission of the Special Operations Peculiar Modification M4A1 Accessory Kit is to provide the M4A1 Carbine and SOF Combat Assault Rifle (SCAR) with the flexibility and versatility to adapt basic issue weapons to meet SOF mission-specific requirements.

Since Special Operations Forces lack organic heavy weapons such as tanks and artillery and are limited in capacity to carry or resupply ammunition, success and survival often depends on the effective employment of individual weapons. Items contained within the SOPMOD Kit enhance the weapon's operational effectiveness through increased target recognition/acquisition, speed of engagement, and accuracy from Close Range Engagements (CRE; designated as engagements between 0 and 50 meters) to the maximum effective range of the weapon (600 meters) during both day and night conditions. Within these mission areas the SOPMOD Program is responsible for the full spectrum of research and development, acquisition, and special operations forces warfighter support.

The Special Operations Peculiar Modification (SOPMOD) Accessory Kit Program, originally for the M4A1 carbine only, was sponsored by the United States Special Operations Command and was responsible for procuring and fielding Non-Developmental Item/Commercial Off-the-Shelf (NDI/COTS) components that increased the operational effectiveness of the M4A1 Carbine in both day and night conditions. It was intended to allow special operations forces operators to configure the M4A1 carbine based on mission-specific requirements. Kit items increased weapons effectiveness through improved target acquisition and fire control in close-quarters battle and out to ranges of 500 meters, both day and night.

Prior to 1989, the only unified method for attaching the wide array of non-standard optical sights, flashlights, and other accessories to weapons used by the special operations community was duct tape and hose clamps. With the establishment of a unified US Special Operations Command in the late 1980s, there became a desire to standardize the various systems in use. In 1989, the first attempt was made with the Special Operations Special Technology (SOST) Modular Close Combat Carbine Project. This program utilized an prototype M4 type carbine supplied with an accessory kit with various optics and mounts, a sound suppressor, a variant of the M203 grenade launcher, and under-barrel shotgun.

Following the SOST Modular Close Combat Carbine Project, the Special Operations Peculiar Modification (SOPMOD) Program came into being in 1992. Its associated Program Management Office, located at the Naval Special Warfare Center, Crane Division in Crane Indiana, was to provide standardized, versatile weapons accessories to meet needs across special operations forces mission scenarios. These accessories were to increase operator survivability and lethality by enhanced weapon performance, target acquisition, signature suppression, and fire control. The SOPMOD PMO was to provide these accessories when they were operationally suitable, affordable, sustainable, and funded.

Component commands were still cautious about buy-in to a new joint program in 1993. As component commands gradually accepted the SOPMOD Program between 1994 and 1998, demand for capabilities and quantities of items increased. However, funding for these new systems did not.

By the end of the 1990s, the procurement/fielding of the Accessory Kit (Phase I) was nearly complete. However, the program was looking to continuously improve the existing kit components, as well as providing new NDI/COTS technologies to special operations forces. The Block I Accessory Kit consisted of the following components: 4x day scope, reflex sight, rail interface system (MIL-STD-1913), vertical forward handgrip, quick attach/detach M203 grenade launcher mount and sight, infrared laser pointer/illuminator, visible laser, visible bright light, back-up rear iron sight (known simply as a back-up iron sight or BUIS), combat sling, sloping cheek weld stock (referred to as the "Crane stock"), mini night sight and 9" M203 grenade launcher barrel.

All kit items were fielded or in production with the exception of the Mini Night Vision Sight (MNVS). Operational testing completed on MNVS in the third quarter FY99, with fielding to follow. Work was subsequently began on supplemental requirements to SOPMOD Generation II, which begans research and development efforts in FY00 and FY01. The Generation II SOPMOD kit (also known as SOPMOD Block II) would concentrate on consolidation of existing devices and new capabilities designed to enhance the lethality of the special operations forces operator.

As of 2001, the Initial Operational Capability for the Block I kit was expected in mid-FY02, with the Block 2 kit appearing in early FY05, and the Block 3 kit in FY08. At that time, the AN/PVS-17 night vision optic and associate mount, the Trijicon Advanced Combat Optical Gunsight (ACOG; which had been selected as the 4x day scope component), and the visible laser component were all expected to be utilized in the Block II kit. The detachable carry handle, BUIS, the reflex sight, AN/PEQ-2 IR pointer/illuminator, quick attach/detach M203 grenade launcher mount and sight, vertical forward handgrip, and combat sling were to be standardized as part of the US Army Modular Weapon System. The reflex sight component of the Block 1 kit had been the Trijicon Reflex II sight. For the MWS, this was replaced by the Aimpoint M68 Close Combat Optic (CCO). The rail interface system handguard, visible light, and sound suppressor were all to be replaced in the Block II kit.

The Block II kit was also to include various new capabilities, including an Enhanced Grenade Launcher Module (EGLM), Enhanced Combat Optical Gunsight (ECOS), and Clip-On Night Vision Device (CNVD). The new optics and sights would provide modular active and passive day and night target acquisition, identification, and aiming for the M4A1 Carbine to 800 meters and EGLM day and night passive and active aiming to 400 meters, with first round hit capability. In addition, the Block II kit would feature specialized upper receivers for long range and close quarters battle (CQB) with matching optics and noise and flash signature reduction. The long range upper was referred to as the Special Purpose Reciever (SPR), while close quarters upper was referred to as the CQB Reciever (CQBR). Development of an Enhanced Carbine, readily configurable in all 3 configurations (standard, CQB, and light sniper/automatic rifle) was proposed for the FY05 time frame.

In 2002, the SPR element was separated from the existing SOPMOD kit, though development remained the responsibility of the SOPMOD Program. The system, to be issued as a complete weapon became known as the Special Purpose Rifle (still SPR), and was eventually designated as the Mk 12. The CQB component followed suit in 2003, becoming the Mk 18 Close Quarters Battle Rifle (CQBR).

In 2003, US Special Operations Command (USSOCOM) also initiated a program known as the Special Operations Forces Combat Rifle (SCR), which was to look for a highly reliable and modular combat rifle for special operations forces as a replacement for the aging M4A1 carbine. This need had been identified with the proposed Enhanced Carbine in 2001. The SCR program was effectively a spin-off from the earlier special reciever programs developed for the SOPMOD kit. Subsequently known as the Special Operations Forces Combat Assault Rifle (SCAR), selected a weapon produced by the Belgian firm FN Herstal in 2004. The SCAR program meant that the SOPMOD kit, previously intended only for the M4A1 carbine, would have to also be capable of being fitted to the new weapon. The SOPMOD Program hoped that by FY06, the SOPMOD Block 2 kit would be compatible with both the SCAR and with the majority of other small arms systems USSOCOM had in inventory.

With this new mandate, SOPMOD began exploring a common family of sound suppressors for special operations forces weapons, as well as a shot counter, again compatible with all weapons. Upgrades to the existing BUIS and rail interface systems for the Block II kit were also proposed.