FN M249 Trigger Mechanism for FN M249, FN M249S

The FN M249 Trigger Mechanism delivers factory-original reliability for military-pattern automatic rifles, with all critical components machined to FN’s exacting specifications. This complete drop-in assembly maintains the M249 platform’s sustained-fire capability without aftermarket compromises.

What you get

• Complete trigger mechanism assembly including trigger frame
• Hardened steel trigger, sear, and safety components
• Trigger guard with integrated pistol grip mounting
• Factory retaining spring and all necessary pins
• FN-marked components identical to military-issue parts

Build and finish

Machined from ordnance-grade steel, the trigger mechanism features phosphate-coated surfaces for corrosion resistance. The sear engagement surfaces receive additional hardening to prevent wear during sustained automatic fire. Tolerances are held to ±0.001″ for reliable ignition across temperature extremes.

The assembly maintains the M249’s distinctive two-stage trigger pull – a 5.5-6.5 lb initial take-up followed by a clean 3.5-4 lb break. All springs are chrome-silicon for consistent tension retention. The pistol grip interface uses FN’s proprietary reinforcement ribs to prevent flex during rapid strings of fire.

Compatible platforms

• FN M249 (all variants)
• FN M249S semi-auto version
• FN MINIMI (5.56x45mm NATO models)
• FN M249 PARA shortened models
• FNH USA/FN America production rifles

Installation notes

Requires armorer-level tools including M249 pivot pin wrenches and headspace gauges. The mechanism must be timed to the bolt carrier group per TM 9-1005-224-23&P. FN recommends professional installation to maintain NFA compliance on select-fire platforms.

As with all FN military-spec components, this trigger mechanism undergoes magnetic particle inspection before leaving the factory. It’s the same reliability that keeps belt-fed rifles running in sand, snow, and jungle – now available for authorized end users through Rare Breed Triggers’ LE/SOT program.