Apex Optic Mount for FNX-45 – ACRO/MPS* Optics

If you’re running an FNX-45 Tactical and want to mount an Aimpoint ACRO P-1/P-2, Steiner MPS, or Lead & Steel Pandora PB-3, you’ve probably noticed the factory mounting setup doesn’t always lock those optics down as tight as you’d like. This Apex Optic Mount solves that problem. It replaces the factory mounting plate with a precision-machined steel plate that gives these specific optics a solid, repeatable zero — no shifting, no loosening over time. It’s a simple swap that keeps your slide cut clean and your optic secure, especially if you’re putting rounds downrange regularly.

Will this fit my gun?

• FNX-45 Tactical models with factory optic mounting cut
• Aimpoint ACRO P-1 & P-2
• Steiner MPS
• Lead & Steel Pandora PB-3
• Does NOT fit standard FNX-45 models without the factory optic cut

Key features

• Machined from billet steel with black oxide finish — tougher than aluminum or plastic
• Mounts directly to the factory slide using included screws with thread locker pre-applied
• If you lose the included screws, you can substitute the short 5-40 mounting screws that came with your FNX-45 Tac
• For the Steiner MPS, we recommend using the Apex Super Clamp to expand clamping range

Install difficulty: 2 out of 5

This is a straightforward swap. You’ll need a small flathead screwdriver or punch to depress the rear sight plunger, a 3/32″ hex key (or similar) for the optic mounting screws, and maybe a torque wrench if you want to be precise. No fitting, no filing — just remove the factory plate, install this mount, torque the screws to spec, and mount your optic. Most folks have it done in under 20 minutes.

Frequently asked questions

Will this work on my FNX-45 without the factory optic cut?

No. This mount is specifically designed for FNX-45 Tactical models that already have the factory optic mounting cut in the slide. It won’t fit non-Tac models.

Do I need to use the Apex Super Clamp with the Steiner MPS?

You don’t have to, but we strongly recommend it. The MPS has a slightly different clamping footprint than the ACRO, and the Super Clamp gives you a wider clamping range to ensure a rock-solid fit. Without it, you might find the optic doesn’t seat as securely.

Can I use my factory screws instead of the included ones?

Yes, if you lose the Apex screws, the short 5-40 threaded screws that came with your FNX-45 Tac will work as a substitute. But the included screws have thread locker pre-applied, so we’d suggest using those first.

Orders ship within one business day from our shop. This mount comes with our standard warranty against manufacturing defects — if something’s off, we’ll make it right. Need help deciding? Give us a call or drop an email; we’re happy to walk you through it.