MRAT Compensator Kit for FNX-45

The MRAT Compensator Kit for the FNX-45 is a direct-thread-on compensator designed to reduce muzzle rise by 40–60% depending on ammunition, enabling faster sight return and more controlled follow-up shots. The kit includes a captive-spring guide rod assembly required for proper function, as the compensator reduces slide velocity. The spring retaining nut is removable for spring replacement and tuning. Tested with SAAMI-spec ammunition from light target loads to +P duty rounds; hand loads below SAAMI pressure may induce malfunctions.

Compatibility

• FN FNX-45 (all generations)
• Threaded barrel required (factory or aftermarket)
• Will not fit non-threaded FNX-45 barrels

Key Features

• Reduces muzzle rise 40–60% (dependent on load)
• Direct-thread installation—no set screws or shims
• Integrated captive-spring guide rod assembly with removable retaining nut for spring tuning
• Wings on comp body cover slide-to-comp gap for streamlined profile
• Cerakote Magpul FDE H-267 finish (as noted; other colors available separately)

Install Difficulty

Difficulty: 2/5. Requires basic hand tools (torque wrench, thread locker). Thread comp onto barrel to spec, install guide rod assembly. No permanent modifications. Approx. 15 minutes.

FAQ

Will this fit a standard FNX-45 barrel?

No. The MRAT requires a threaded barrel. Factory FNX-45 threaded barrels are compatible; aftermarket threaded barrels must match the factory thread pitch (.578×28).

What spring weight is included?

The kit includes a standard captive spring tuned for SAAMI-spec ammunition. The retaining nut allows swapping to a lighter or heavier spring for custom tuning with specific loads.

Can I use hand loads?

Hand loads with less than SAAMI-spec pressure may cause malfunctions. The comp was tested with factory loads from 115gr target to 230gr +P. For reliable function, use factory ammunition or loads matching SAAMI pressure.

All MRAT kits ship with a 30-day warranty against manufacturing defects. Free shipping on orders over $100. Not responsible for malfunctions from non-SAAMI ammunition or improper installation.