In this guide, we will explain the footprint and mounting of the Holosun SCS Carry 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 the Holosun SCS Carry 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 two handguns on the left are 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 Holosun 507C), and the handgun on the right is a compact (Springfield Hellcat with Holosun SCS Carry).
The Holosun SCS Carry is a compact red dot intended for smaller compact handguns. If you have a full-size handgun, consider the Holosun EPS or Holosun 507C instead.
The Holosun SCS Carry Mounting Footprint
The Holosun SCS Carry has a modified version of the Holosun “K” mounting footprint. It also includes an adapter plate for the more common RMSc (or Shield) footprint.
In the picture below, you can see the footprint on the Holosun SCS Carry along with the included adapter plate.
The RMSc footprint is the most popular footprint for compact slide handguns. It has four posts, one in each corner, and two screws near the rear of the sight.
The Holosun “K” footprint is similar to the RMSc. The rear posts have been removed and the front posts are shorter.
In general, handguns that are compatible with the Holosun “K” footprint are also compatible with the RMSc footprint. However, not all handguns with the RMSc footprint are compatible with the Holosun K Footprint.
Some handguns like the Sig Sauer P365, Ruger Max-9, S&W Equalizer, and the FN Reflex MRD have slides that are compatible with both the Holosun K footprint and the RMSc footprint. In these cases, the included adapter plate is not needed. This results in the optic sitting lower on the slide (which helps with using backup iron sights). The picture below shows the Sig P365 and the Holosun SCS Carry without the included adapter plate.
Other handguns like the Springfield Hellcat, Glock 43X and 48 MOS, S&W M&P Shield, and the Walther PPS are only compatible with the RMSc footprint. In these cases, the included adapter plate must be used to mount this optic to these handguns since the rear posts are present. The picture below shows the Springfield Hellcat Pro and the Holosun SCS Carry with the included adapter plate.
Note that the included adapter plate does not require any additional screws like most adapter plates do. The plate is sandwiched between the optic and the slide, and the screws that hold the optic to the slide pass through it. This results in it being only 0.053 inches (1.35mm) thick and keeps the optic as low as possible on the slide.
Will the Holosun SCS Carry Fit your Handgun?
The Holosun SCS Carry will fit any compact handgun that is optics ready and has an RMSc footprint. Some compact handguns that are compatible with the Holosun K footprint may not require the included adapter plate. This will allow the optic to sit lower on the slide, which is desirable.