This is the suppressor you need for your USMC M40A5 build.
The FA762SS sound suppressor features a barrel overlap design that adds just 5.5 inches to the original length of your AR-10, Bushmaster A2 and A3, M1A, M14, or other semi-auto or bolt action rifle while providing superior sound suppression. The extra-tight suppressor bore is especially suited for sniper rifles. The overlap design requires at least 2.75" of clear barrel with a maximum diameter of .775", measured from the muzzle rearward. Rifles with larger diameter barrels may use the FA762MG sound suppressor.
All SureFire sound suppressors require an adapter for attachment to a firearm. Adapters for the FA762SS sound suppressor screw directly onto the original rifle muzzle threads—see Parts and Accessories below.
Chosen by the US military, SWAT teams, and law enforcement agencies across the country, proven in the world's toughest combat conditions, only SureFire sound suppressors for rifles and machine guns combine every important suppressor feature: excellent sound, flash, and dust signature reduction—key components of SureFire's Total Signature Reduction™ (TSR); minimal and consistent zero shift regardless of attach/detach cycles; rock-solid attachment in seconds; compact size; minimal weight; fail-safe baffles to prevent bullet side-exit; and extreme durability permitting full-time use—in fact, your SureFire suppressor should outlast your firearm barrel.
All SureFire Fast-Attach® sound suppressors provide crucial tactical benefits—they protect shooter and team members against both permanent and temporary hearing loss, enhancing situational awareness and communication; reduce sound signature, concealing shooter's position; reduce or virtually eliminate muzzle flash and dust signatures, concealing shooter's position, preserving night vision and unobstructed view; reduce recoil, improving bullet impact observation and allowing faster follow-up shots.
High-performance sound attenuation
Rock-solid attachment in seconds without tools
Minimal and consistent zero shift regardless of number of attach/detach cycles
Redundant-welded subcomponents eliminate parts loosening
Compact size and light weight, allowing full-time use
Machined from heat-treated stainless steel, finished in a tough, corrosion-resistant coating
Extreme resistance to heat and gas/particle erosion due to special alloy construction