MRAT Compensator Kit for FNX-45

If you’re shooting an FNX-45 and want to cut down on muzzle rise without a ton of hassle, the MRAT Compensator Kit is a solid, direct-thread solution. It’s designed to reduce muzzle rise by 40–60% depending on what you’re feeding it, which means faster sight recovery and less work for your hands between shots. The kit comes with a captive-spring guide rod assembly — that’s a must, because the comp slows slide velocity enough that your stock setup won’t cycle right without it. The spring retaining nut is removable too, so you can swap springs or tune the action if you’re running different loads.

Compatibility

• FN FNX-45 (all generations)
• Direct-thread installation — no barrel threading or gunsmithing needed
• Tested with SAAMI spec ammunition from light target rounds to +P duty loads
• Not recommended for hand loads below SAAMI spec pressure (may cause malfunctions)

Key Features

• Reduces felt recoil and muzzle rise for flatter shooting
• Faster sight return after each round fired
• Wings on the comp body cover the gap between slide and comp for a streamlined look
• Included captive-spring guide rod with removable retaining nut for spring tuning
• FDE finish is Cerakote Magpul FDE H-267 — matches factory FDE nicely

Install Difficulty: 2 out of 5

You’ll need a standard set of punches and a small hammer to swap the guide rod assembly. The comp threads on by hand — no barrel work required. If you’re comfortable field-stripping your FNX, you can handle this in about 15 minutes. Watch our install video on the product page for a walkthrough.

Frequently Asked Questions

Will this fit my FNX-45 Tactical?

Yes, it fits all FNX-45 models, including the Tactical. The comp threads directly onto the factory barrel threads.

Do I need to change my recoil spring?

The included captive-spring guide rod is tuned for the MRAT with most SAAMI spec ammo. If you switch to lighter or heavier loads, you can swap the spring using the removable retaining nut — but for standard 230-grain FMJ or +P hollow points, it’s good to go out of the box.

Why does the kit include a guide rod?

The comp reduces slide velocity, so the factory guide rod won’t have enough spring pressure to cycle reliably. The captive rod in the kit is matched to the comp’s performance. Don’t run the comp without it.

Shipping & Warranty: We ship within 1 business day from our shop in Texas. This kit comes with our standard one-year warranty against defects in materials and workmanship. If you have questions about fit or tuning, give us a call — we’re happy to help.