SOPMOD (acronym for Special Operations Peculiar MODification) is a modular accessory system developed for the M4A1 carbine and compatible weapon platforms such as the CQBR, FN SCAR Mk 16/17, and HK416, primarily used by United States Special Operations Command (USSOCOM) special forces units. The kit allows U.S. Special Operations Forces (US SOF) personnel to configure their weapons according to individual preferences and customize them for different mission requirements.
The SOPMOD kit is composed mostly of non-developmental items and commercial off-the-shelf (NDI/COTS) accessories packaged together to support four M4A1 carbines. It allows for the attachment of any Picatinny-compatible accessory that fits the length of the weapon.
History
The program dates back to September 1989, when the Special Operations Special Technology (SOST) Modular Close Combat Carbine Project was founded. This was the first program to standardize components from the 1970s/1980s era of "duct tape and hose clamps." The Material Need Statement (MNS) was signed in May 1992, and by September 1993, the Operational Requirements Document (ORD) for the program was validated. Responsibility for the program was then assigned to the Naval Surface Warfare Center Crane Division.
Block I
The original SOPMOD Block I kit included the following components:
- Knight's Armament Company (KAC) Rail Interface System/Rail Adapter System (RIS/RAS) forearm with rail covers of various lengths
- KAC Vertical Foregrip (VFG)
- KAC 300m backup iron sights (BUIS)
- Trijicon TA01M4A1 4×32mm Advanced Combat Optical Gunsight (ACOG)
- Aimpoint ECOS-N (Enhanced Combat Optical Sight-Navy), a variant of the CompM2
- Tactical Ordnance and Equipment Improved Combat Sling
- Precision Reflex, Inc. (PRI) M69 Bracket Mount for the AN/PVS-14 night vision device
Per kit (two of the following):
- Insight AN/PEQ-2 Infrared Target Pointer/Illuminator/Aiming Laser (ITPIAL)
- Insight Visible Light Illuminator (VLI)
- Trijicon RX01M4A1 1×24 Dual Illuminated Reflex Sight
- KAC NT-4 Quick-Detach Sound Suppressor (QDSS) kit
Per kit (one of the following):
- M203A1 Grenade Launcher with a 9-inch barrel
- KAC M203 Grenade Launcher Quick Release Front Bracket
- Quick-attach M203 Grenade Launcher Leaf Sight
- Insight AN/PEQ-5 Carbine Visible Laser (CVL)
- Insight AN/PAQ-4 Infrared Aiming Light
- AN/PVS-17A Mini- Night Vision Sight
- AN/PSQ-18A M203 Day/Night Sight
- Carrying/storage case for kit accessories
Additional items (not always issued with kits) included gas-deflecting charging handles, extraction parts sets, Redi-Mag, Lewis Machine and Tool Company (LMT) / B5 Systems Sloping Cheekweld Stock, ambidextrous selector switches, Visible Bright Light II (VBL II), and High Reliability Magazines (HRM).
Block II
The Block II program (also known as the Miniature Day-Night Sight / MDNS program) included phased replacement components and new additions:
- Daniel Defense M4A1 RIS II (Rail Interface System), GL/SSC RIS II, and MK18 RIS II free-float handguards
- Insight M3X VBL III Gun Light (SU-233/PVS) and M6X VBL III Integrated Gun Light (SU-238/PVS)
- Insight WMX 200 Tactical Weapon Light
- EOTech 553 Holographic Weapon Sight (SU-231/PEQ) and EOTech EXPS3-0 (SU-231A/PEQ)
- Insight LA-5C/PEQ ATPIAL (Advanced Target Pointer Illuminator Aiming Laser)
- Insight CNVD-T Thermal Sight (SU-232/PAS)
- Elcan SpecterDR 1–4× Scope + Docter MRD (SU-230/PVS)
- Trijicon ACOG TA31ECOS 4× Scope + Docter MRD (SU-237/PVS)
- Insight AN/PVS-24 Clip-On Night Vision Device (CVND-I2)
- EOTech M40GL Grenade Launcher Sight (SU-253/PEQ ECOS-GL)
The SOPMOD program has had a significant influence on modern personal firearms innovation, particularly through the widespread adoption of the MIL-STD-1913 Picatinny rail system. Over 70,000 kits have been produced, and the system continues to evolve with improved replacements for components as they become available.
