Optics ready plates for Sig P320-M18

The Sig Sauer P320-M18 is a compact military-style pistol with an optics-ready slide and removable rear sight plate. When you take off the factory night-sight plate to mount a red dot, you also remove the rear sight – so the choice of adapter plate matters a lot for your sight picture.

In this category you’ll find optics ready plates made specifically for Sig P320-M18 optics-ready slides. They are designed around the factory ROMEO1 PRO / DeltaPoint Pro–style cut and the configuration where the rear sight is integrated into the cover plate.

Understand your P320-M18 optics cut

Your P320-M18 slide is factory-cut for SIG’s ROMEO1 PRO–type footprint with a combined optic cover and rear sight plate. Once that plate is removed, the slide is ready for a red dot but no longer has a rear sight installed. That’s why many of the plates here either:

• add an integrated rear sight to restore a traditional sight picture, or
• provide a new rear dovetail / co-witness solution so you can keep backup irons with your optic.

Some adapter plates listed here are also compatible with other models that share the same cut (for example certain P320-M17 or Legion slides), but this category is curated around the P320-M18 user so you don’t have to sort through all P320 variants.

Plates available for major red dot footprints

The adapter plates in this category cover a broad range of popular red dot footprints (plate-dependent), such as:

• Trijicon RMR / SRO
• Holosun 407C / 507C / 507Comp and similar RMR-footprint optics
• Leupold DeltaPoint Pro / SIG ROMEO1 PRO–type patterns
• Shield RMSc
• Holosun K-Series
• Noblex / Vortex Venom
• Aimpoint ACRO
• C-More RTS

Always check the individual product description for the exact combination of P320-M18 slide + optic footprint that each plate supports. If a plate also fits M17 or P320 Legion slides, this will be clearly mentioned in the description.

Precision fit for P320-M18 optics-ready models

Every plate is CNC-machined for the Sig P320 optics-ready slide family that shares the M18-style cut. In this category you’ll find:

• Low-profile plates that keep the optic as close to the bore axis as possible.
• Plates with integrated rear sights or rear-dovetail solutions for slides that lose the rear sight with the cover plate.
• Competition- and duty-focused plates that maximize durability and window exposure while holding zero under recoil.

This makes it easy to set up your M18 for carry, duty, or sport while maintaining a secure mount and reliable zero.

Iron sights & backup options

If you want a classic sight picture or backup to your red dot, we also offer iron sights for Sig P320 optics-ready models – including suppressor-height, fiber optic, and tritium sets. For P320-M18 slides, look for plates that reintroduce a rear notch or accept a rear sight directly on the plate to keep usable irons with your optic.

Have a non-OR Sig P320?

If your Sig P320 is not optics-ready from the factory, you can still add a red dot using dovetail or dedicated mounting solutions. Explore our red dot mounts for non-OR Sig P320 pistols here.

Need plates for other Sig models?

Looking for different Sig pistols or other P320 variants? Check our complete range of optic adapter plates for Sig Sauer models.

Not sure which plate fits?

If you’re unsure which exact slide you have or which plate matches your optic, just contact us. Send us “Sig P320-M18” in the message, add the full model name and (ideally) a photo of the slide cut, and we’ll help you choose the right adapter plate for your setup.