Footprints/Mounting Standards on Red Dot Sights

Note: This article is updated constantly. Last update: 15 January 2024.

Introduction

With every passing year, more red dot sights are available on the market. There have never been as many optics manufacturers as there are now, which means that there have never been as many different optical devices as there are now.

Red dot sights have been steadily gaining in popularity – for this reason, they can be found in the offer of most manufacturers of optics around the world. Even companies such as Kahles and Leica, who haven’t manufactured red dot sights before, have recently launched their own versions.

Click here to see our database of all footprints of red dot sights

Terminology

When this article was first written, there was some inconsistency in the use of terminology. This is why we decided to dedicate this paragraph to explaining the differences between the terms screw hole pattern, bolt pattern, socket pattern, mounting standard, and footprint.

Screw hole pattern

The screw hole pattern refers to the screw hole (bolt) position on a red dot sight.

Bolt pattern

This is just another term used to refer to the screw hole pattern. 

Socket pattern

The socket pattern refers to the dimensions and distances between the sockets on the red dot sight’s mounting surface.

Mounting standard

The screw hole pattern (bolt pattern) and the socket pattern form a mounting standard. Red dot sights that share a mounting standard can be mounted on the same adapter.

With Aimpoint Acro, Holosun 509T, and some other standards, there are neither screw holes nor any sockets on the mounting surface. When using the term ‘mounting standard’ to talk about these sights, we refer to the dimensions of the clamping mechanism on the red dot sight’s mounting surface.

Footprint

The term footprint encompasses the mounting standard and the entire bottom surface of the red dot sight. To give you a better understanding, if the mounting surface was pressed into the sand, the three-dimensional imprint would show (match) the footprint of the device.

Differentiating between these terms is important, especially if you have a custom pistol slide cut. In that case, you want the red dot sight to sit in the cutout perfectly, so taking only the mounting standard into account is not enough; you want a red dot sight whose footprint matches the cutout perfectly.

In this article, the most common mounting standards used on red dot sights are listed. Each standard is described and an image of it is added. Within each mounting standard section, the red dot sights that share it are enumerated. Next to each sight, there is a link to the dimensions of its footprint (we will gradually be adding these).

Docter/Noblex mounting standard

This is one of the most widely used mounting standards in the field of red dot sights. It has two holes for screws and four sockets in which the pins on the mount/adapter fit, one in each corner. There is a wide range of mounts for this mounting standard on the market, which is one of the main reasons why it is used by so many manufacturers. Docter/Noblex standard is simple and reliable.

Red dot sights that share this mounting standard:

* These red dot sights have a Docter/Noblex mounting standard, but the adapter supplied with them has wider threaded sockets than adapters suited for a Docter/Noblex mounting standard. Consequently, thicker screws are enclosed. You can mount these red dots on an adapter designed specifically for the Docter/Noblex mounting standard, but you will not be able to use the screws supplied with them – thinner screws are needed.

**The screw holes do not accept a 6-32 screw.

Note: distances between holes (sockets) are measured from and to the center of the hole (socket).

Modifications of the Docter/Noblex mounting standard

The following red dot sights come with a mounting surface that is very similar to the one used by Docter:

The four sockets, one in each corner, are in the exact same places. The holes for the screws, however, are not. This is why Meopta Meosight III, Delta Optical MiniDot HD 25, and Meprolight MicroRDS cannot be mounted on every adapter designed for the Docter/Noblex mounting standard. Several adapters are designed so that red dot sights with a Docter/Noblex mounting standard and Meopta Meosight III/Delta Optical MiniDot HD 25/Meprolight MicroRDS can be mounted on them (see the images below).

Aimpoint Micro mounting standard

Aimpoint is the first company to have used this mounting standard on their Micro small tube sights. Today, other manufacturers of this type of sights use it as well. The surface of the mounting surface is slightly lifted in the middle – on each side of the lifted section, there are two holes for screws. The lifted section is cut in the middle – this is where the recoil stop fits.

Red dot sights that share this mounting standard:

Modifications of the Aimpoint Micro mounting standard

Red dot sights that feature a modified Aimpoint Micro mounting standard:

• GPO Spectra
• Hawke Endurance 1×25
• Hawke Endurance 1×30
• Rudolph Optics 1×20
• Vector Optics Maverick-IV 1×20 Mini
• ADE Advanced Optics RD4-005

GPO Spectra uses a mounting surface that is identical to the one used by Aimpoint Micro. Even though it appears to be the same at first sight, there is a protruding part underneath the illumination knob. Because of it, the adapters designed for the Aimpoint Micro mounting standard do not fit into place at that side (check the picture below). GPO Spectra uses a unique adapter with narrow side sections.

Hawke Endurance 1×25 and 1×30 red dot sights also use a mounting surface slightly different from the Aimpoint Micro one. The lifted section in the middle is wider, thus adapters designed for the Aimpoint Micro mounting surface do not fit in place.

Rudolph Optics 1×20 Footprint

This red dot sight features a modified Aimpoint Micro mounting standard – the recoil notch in the middle of its footprint is missing. Nearly all mounts designed for the Aimpoint Micro mounting standard come with a recoil stopper in the middle, which is why it is nearly impossible to find an aftermarket adapter made by a renowned mounts manufacturer for Rudolph Optics 1×20.

Vector Optics Maverick-IV 1×20 Mini Footprint

This red dot sight features a modified Aimpoint Micro mounting standard. The distance between the two screw holes on each side of the recoil stopper is 8.8 mm instead of 10 mm. Because of this, Vector Optics Maverick IV 1×20 Mini is not compatible with adapters designed for the Aimpoint Micro mounting standard.

ADE Advanced Optics RD4-005 Footprint

This red dot has a modified Aimpoint Micro mounting standard. The recoil notch in the middle of its mounting standard is narrower, measuring the same as a Weaver recoil notch, 3.8 mm. Furthermore, the distance between the screw holes in the front and in the rear is 2 millimeters bigger than on Aimpoint Micro mounting standard.

C-more RTS/STS mounting standard

This is a mounting standard found on C-more’s popular red dot sights, RTS and STS. Some other manufacturers also use it because of its simplicity and reliability. The standard consists of two holes for screws and two sockets in which the pins on the mount/adapter fit.

Red dot sights that share this mounting standard:

Shield RMS/SMS mounting standard

Shield sights are incredibly compact, which is why Shield had to come up with a mounting standard of their own. It is designed similarly to the Noblex/Docter mounting standard (there are two holes for the screws and four sockets in which the notches on the mount/adapter fit, one in each corner). The sockets, however, are a little bit wider and closer one to another.

Red dot sights that share this mounting standard:

Important notes

Even though Shield RMS and RMSc differ in dimensions (the ‘c’ version is smaller), the distances between the holes are the same, which is why an adapter designed for the Shield mounting standard fits on both.

• RMSc -(length x width x height) 40 x 23 x 22 mm
• MS  – (length x width x height) 42 x 25 x 23 mm

Modifications of the Shield RMS/SMS mounting standard

Leupold DeltaPoint Pro mounting standard

Even though Leupold DeltaPoint Pro fits on mounts designed for the Shield RMS/SMS mounting standard, it does not result in a secure fit, because its sockets are wider than the pins on adapters for Shield RMS/SMS. Therefore, mount manufacturers usually produce mounts specifically for the Leupold DeltaPoint Pro. Furthermore, red dot sights with the Shield RMS/SMS mounting standard do not fit on mounts designed specifically for the Leupold DeltaPoint Pro.

The four sockets on Leupold DeltaPoint Pro’s mounting surface are wider than those on a Shield RMS/SMS mounting standard. Namely, the sockets measure 4.2 mm in diameter, while the sockets the Shield RMS/SMS mounting standard measure 3.8 mm in diameter.

Red dot sights that feature this mounting standard:

Holosun 407/507K mounting standard

The differences are:

• the two rear sockets are missing (see the photo below)
• the sockets in the front are shallower (see the photo below)

For this reason, some pistols that are optic-ready for the Shield mounting standard need to be modified for the 407 and 507K. Namely, the two rear indexing lugs on the pistol have to be removed and the two front indexing lugs shortened in height. Hellcat and Walther PPS are examples of such pistols (some pistols, such as Sig Sauer P365XL, do not have to be modified).

Holosun EPS mounting standard

The red dot sights listed below feature a mounting surface modified even more extensively (compared to the Holosun 407/507K modification):

• Holosun EPS Footprint
• Holosun EPS Carry Footprint

The mounting surfaces of these red dot sights have the same modifications as those found on Holosun 407/507K devices, with an addition of the following features:

• There are two additional sockets in the front part of the mounting surface, placed in between the usual ones. Holosun produces plates that convert this specific mounting surface to the other ones (Trijicon RMR, for example).

Trijicon RMR mounting standard

This mounting standard consists of two holes for screws and two sockets in which the pins on the mount/adapter fit – these are in the front, in each corner. Even though the sockets are in the front only, the mounting standard is somewhat reminiscent of the Docter/Noblex one. Note, however, that the sockets in the corners are farther apart on the Trijicon mounting standard and bigger in diameter.

Red dot sights that share this mounting standard:

Modifications of the Trijicon RMR mounting standard

Red dot sights that feature a modified Trijicon RMR mounting standard:

• ADE Advanced Optics RD3-019 Stingray Footprint

This red dot sight has two additional sockets on its mounting surface. They are located in each of the rear corners. Furthermore, the sockets are 0,1 mm narrower and the screw holes are 0,4 mm wider than on the standard RMR mounting standard. Nevertheless, mounts designed for the Trijicon RMR mounting standard can be mounted on ADE Advanced Optics RD3-019 Stingray.

Trijicon MRO mounting standard

This mounting standard comprises four screw holes, two in the front, two in the rear. The holes on the left are separated from the holes on the right with a lifted section in the middle.

Red dot sights that share this mounting standard:

Important notes (Burris RT-1X)

Burris RT-1X’s mounting standard is the same as the one on Trijicon MRO, but there is a difference in the supplied screws. RT-1X comes with screws that have bigger heads than the ones supplied with the MRO, which is why you cannot use them to fix an original Trijicon adapter on the Burris red dot. If you wish to mount an original Trijicon adapter on the Burris RT-1X, you have to use the screws supplied with the Trijicon adapter (see the picture below).

Modifications of the Trijicon MRO mounting standard

Vector Optics Centurion 1×30 features a modification of the Trijicon MRO mounting standard. The distances between the screw holes are the same, and so is the thread. The difference is in the lifted section. On Centurion, the middle part of the lifted section is cut out to create space for a recoil stop. For this reason, a mount designed for the Trijicon MRO mounting standard fits on the Centurion, while a mount designed for the Vector Optics Centurion (with a recoil stop) does not fit on the MRO (the middle part of the lifted section is not cut out).

Glock MOS mounting standard

Glock devised the MOS system in 2015. MOS stands for Modular Optic System. This was one of the first optic-ready sistems introduced on a pistol, and the standard has been gaining in popularity ever since. There are two screw holes between the front and the middle part of the mounting surface. Usually, a plate is used to convert the MOS standard to any other ones, but some red dot sights are designed to fit directly on it.

Red dot sights that share this mounting standard:

Walther PDP 2.0 mounting standard

Walther’s PDP models are optic-ready, but there is a difference between the cuts of 1.0 and 2.0 models, so you have to be careful if you are looking for a mounting plate. Red dot sights with this mounting standard are designed to fit directly on the Walther PDP 2.0 models, no additional plates are required. There are two screw holes for mounting purposes. See the image below for more details.

Red dots that share this mounting standard:

• Holosun SCS PDP Footprint

Heckler & Koch VP9 mounting standard

This mounting standard is compatible with Heckler & Koch VP9 optic-ready pistols. Red dot sights equipped with it fit directly on the pistol cut, no additional plates are required. There are two screw holes for mounting purposes – check the other characteristics of the standard in the image below.

Red dots that share this mounting standard:

• Holosun SCS VP9 Footprint

Smith & Wesson M&P 2.0 mounting standard

This mounting standard is designed to fit directly onto the cut of Smith & Wesson M&P 2.0 optic-ready pistols, without having to use an additional plate. There are two screw holes for mounting purposes – the other features can be observed in the image below.

Red dots that share this mounting standard:

• Holosun SCS MP2 Footprint

Aimpoint Acro mounting standard

Aimpoint designed a new mounting standard for their Acro red dot sights. There are grooves on the side of it with a movable part used to fix the red dot sight in place. The movable part is connected to a recoil stopper. The system is similar (but not the same) as the one designed for a Picatinny rail.

Red dot sights that share this mounting standard:

Note: distances between holes (sockets) are measured from and to the center of the hole (socket).

Important notes (Steiner MPS)

Steiner MPS features the same mounting standard as Aimpoint ACRO but its footprint is slightly different. The grooves in which the adapter fits are not in the exact same place but the recoil notch is. This is why adapters designed for Aimpoint Acro can be mounted on MPS as well. The same applies to Vector Optics Frenzy Plus 1x18x20.

Aimpoint CompM4 mounting standard

The screw holes, one on each side of the mounting standard, are located on the lifted sections which work as recoil stoppers when fixed on an adapter. The same applies to the lifted section in the middle.

Red dot sights that share this mounting standard:

C-More Railway mounting standard

This is one of the longest mounting surfaces available in red dot sights. There are two screw holes on it for mounting purposes. The mounting surface is flat.

Red dot sights that share this mounting standard:

Modification of the C-more Railway mounting standard

The following red dot sight uses the same form factor but the mounting solution is completely different.

• C-More Serendipity Footprint

The dot is attached to the pistol by means of drilling and tapping the frame via the integral polymer mount.

C-MORE SERENDIPITY INSTALLATION

The Serendipity was originally designed to attach to 1911 style handguns for competition shooting by drilling and tapping the frame and mounting the sight directly via the integral mount.

The mounting legs allow for a maximum slide width of .950″ (A).
The mounting legs allow for a maximum slide height of 1″ (B).
The mounting pads can be machined to accomodate frame widths between .750″ and 1″ (C).

Holosun AEMS mounting standard

Holosun introduced this mounting standard in 2022 on AEMS and AEMS Core models. There are two sockets in the front part, a screw hole next to each of these sockets, and two more screw holes close to the central part of the surface. There is a recoil stop between the screw holes.

Red dot sights that have a unique mounting standard

• Trijicon RMRcc Footprint

Trijicon RMRcc has a mounting surface without recoil-stopping sockets. There are two holes for screws between the middle and rear section. The size of the mounting standard is similar to Shield RMS/SMS, Leupold Delta Point Pro, Holosun 407/507K, etc.

• Holosun 509T Footprint

This red dot sight has a unique mounting surface that works similarly to the mounting standard designed for the Picatinny rail. The adapters suitable for it are slid into place and then fixed with the movable side section. A recoil stop helps keep the adapter in place.

• Holosun Infinity models

The mounting surface of the Infinity models is flat, with three notches for recoil stoppers. The adapter is fixed in place with four screws.

• Sig Sauer Romeo 1 1×30 Footprint

Sig Sauer’s Romeo 1 1×30 has a mounting standard suitable for mounting on certain Sig Sauer pistols – you will need a special adapter if you wish to mount it elsewhere.

• Steiner MRS
• Steiner MRS Universal

All Steiner MRS red dot sights share the same mounting standard – there are only two narrow notches in the front, while the holes for the screws are located at the rear of the sight, on both sides, left and right.

The ‘Universal’ model, however, is supplied with an adapter that converts the mounting standard into the one designed for Docter/Noblex adapters.

• Holosun Paralow 403A

• Holosun 510C Footprint

Holosun 510C has 10 screw holes on its mounting surface, 6 in the front and 4 in the rear. There are two lifted sections in the middle which work as recoil stoppers.

• DI Optical RV2

• Vector Optics Nautilus 1×30 Footprint

Even though the mounting standard found on Vector Optics Nautilus 1×30 looks identical to the one on DI Optical RV2, there are minimal differences between the two. The lifted sections with screw holes are narrower on RV2. Because of some other minimal deviations, the supplied adapters are not interchangeable between these two sights.

• Sightmark Volta Footprint

The mounting standard on Sightmark Volta is somewhat similar to the Aimpoint Micro mounting standard, but the distance between the front and rear holes is bigger. Furthermore, the recoil notch is wider.

• Vector Optics Wraith 1x22x33 Footprint

The mounting standard on Vector Optics Wraith 1x22x33 is an enlarged version of the Docter/Noblex mounting standard. There is a socket in each of the four corners and two screw holes in the rear part of the surface.

• ADE Advanced Optics RD3-011 Avenger Footprint

This mounting standard is similar to the one on Vector Optics Wraith, but the distances between the sockets and the screw holes are not exactly the same. There are four sockets, one in each corner, and two screw holes in the rear part of the surface for mounting purposes.

A list of all the red dot sights, their mounting standards and footprints

Red dot sights with an integrated Picatinny mount

Red dot sights with an integrated Blaser mount

Adapter plates

An adapter plate is needed if you wish to mount a red dot sight on your handgun. As there are red dot sights with different mounting standards on the market, it is important to pick the suitable one. Some handguns are optic-ready and come with a mounting standard-specific plate. In the following link, you will find a vast selection of red dot sight plates that either fit directly on a specific handgun or convert the existing mounting standard to make it compatible with another mounting standard:

Optic ready handguns

The popularity of optic ready handguns is on the rise. Do you have an optic ready handgun and wish to know how to mount a red dot sight on it? We are working on making it simpler for you. Below is a list of all the optic-ready handguns we have examined so far.

If you have a compact reflex or small tube sight that isn’t listed in this article, please be so kind as to send a picture of the sight and its footprint to [email protected] – help us expand our database. We greatly appreciate everyone’s help!

This article is regularly updated with new information and user contributions. We aim to create a collection of useful data that will be of great help to users, potential buyers of red dot sights, and those who are looking for a specific mount/adapter for their red dot sight.

Summary

Article Name

Footprints on red dot sights

Description

In this article, the most common footprints/mounting standards used on red dot sights are listed. Each standard is described and an image of it is added.

Author

Andraž Gradišnik

Publisher Name

Optics Trade Blog

Publisher Logo