In this guide, we will explain the footprint and mounting of the Sig Sauer Romeo X Pro red dot so you can be sure that it is compatible with your pistol.
Red dots are not made to a particular industry standard, so it is important to know which red dot is compatible with the handgun you want to use it with.
We will cover what to look for on your existing handgun and the specifics of Sig Sauer Romeo X Pro mounting footprint.
Optics Ready Handgun
First, your handgun must be optics ready to mount a red dot to the slide. Handguns that are optics ready typically come with cover plate on the slide near the rear sight. This cover plate covers the red dot mounting surface when a red dot is not being used. In some cases, the cover plate may include the rear sight.
In the picture below the handgun on the left is optics ready, while the handgun on the right is not.
The mounting pattern that is machined into the handgun slide for the red dot is called the mounting “footprint”. This footprint is not an industry standard and can vary between handguns and red dots. Check the manual that came with your handgun for details on how to remove the cover plate and what red dot footprint your handgun has. Also compare it to our photos below.
Handgun Size
Next, it is important to understand if your handgun has a “full-size” slide or a “compact” or “slim” slide.
Full size handguns typically have a slide that is about 1.0 to 1.1 inches wide. Some examples are the Glock 19, Walther PDP, and Sig Sauer P320.
Compact size handguns typically have a slide that is about 0.8 to 0.9 inches wide. Some examples are the Sig Sauer P365, Glock 43X MOS, and the Springfield Hellcat.
In the picture below, the handgun on the left is full size (Walther PDP with the Romeo X Pro), and the handgun on the right is a compact (Sig Sauer P365 X-Macro with the Romeo X Compact).
Note that there are two versions of the Romeo X red dot. The Romeo X Compact is a compact size red dot intended for smaller compact handguns (shown on the right above). The Romeo X Pro is a full-size red dot intended for full-size handguns (shown on the left above). If you have a compact handgun with a slim slide, consider the Romeo X Compact instead.
The Sig Sauer Romeo X Pro Mounting Footprint
The Sig Sauer Romeo X Pro has the DeltaPoint Pro (DPP) mounting footprint. This footprint has four posts, one in each corner, and two screws near the rear of the sight.
In the picture below, you can see the DeltaPoint Pro footprint on the optic plus two handguns with Delta Point Pro footprints.
Many full size optics ready handguns like the Glock MOS and Walther PDP have proprietary footprints that require adapter plates. Some come with adapter plates included, while others must be ordered separately.
For example, The Glock 19 MOS handgun comes with an RMR adapter plate. However, it does not come with a DPP plate.
The Walther PDP does not come with any adapter plates, but they can be ordered directly from Walther (the first one is free). Simply select the “DeltaPoint Pro” plate when ordering.
The Sig P320 comes with the DPP footprint already machined on the slide, so no adapter plate is needed.
For your handgun, consult the manual and compare it to our picture of the DPP footprint above. If your handgun does not have a DPP compatible plate or slide, an adapter plate is needed. We have noted some compatible handguns and if an adapter plate is needed below:
- Sig Sauer P320 (no adapter plate needed)
- Glock MOS (not 43x or 48) – Glock MOS to DPP Adapter Plate required (adapter plate noted below)
- Smith & Wesson M&P 2.0 - Smith & Wesson M&P 2.0 to DPP Adapter Plate required
- H&K VP9 - H&K VP9 to DPP Adapter Plate required
- CZ P-10 - CZ P-10 to DPP Adapter Plate required
- Walther PDP - Walther PDP 2.0 to DPP Adapter Plate required (note this is for the PDP 2.0 only)
Will the Sig Sauer Romeo X Pro Fit your Handgun?
The Sig Sauer Romeo X Pro will fit any handgun that is optics ready and has a compatible DPP footprint. Some handguns that have a proprietary adapter plate system or are cut with a different footprint may need an adapter plate.