UTG Super Slim RDM20 Mount for Glock Rear Sight

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Glock Dovetail · Docter Footprint · Low Profile
UTG RDM-20GL: Red-Dot Upgrade without MOS or Milling Work
The RDM-20GL replaces the rear sight in the Glock dovetail and creates a very low-profile mount for compact optics with Docter-/Venom-/Noblex footprint.
Key point: This is a reversible dovetail solution, not a milled direct optic cut. It is not suitable for RMR, ACRO, or Aimpoint Micro.

Our honest assessment
For training and range use, the RDM-20GL is a pragmatic way to test or build a Glock without MOS system with an MRDS. The low height keeps the optic relatively close to the slide. If you want maximum long-term durability for tough professional use, a suitable direct cut is usually more consistent.


Works well if … … you use a Glock double stack without MOS, don’t want permanent modification, and your optic really has the Docter-/Venom-/Noblex footprint.


Less suitable if … … you use Glock G44, RMR-, ACRO-, or Aimpoint Micro footprint or expect a permanently maximally durable duty solution.


Features and practical effect


Rear-Sight Dovetail The mount uses the existing rear sight slot. The slide does not need to be milled; however, the original rear sight is removed.


0,
15 inch saddle height The flat design reduces additional sight height and helps keep the setup compact.


6061-T6 aluminum Low weight with a compact design. Stability also depends on a clean dovetail fit and correctly mounted optics.


Locking Torx + Insert Torx screws and dovetail insert secure the connection. After installation and first use, a fit check is mandatory.


Avoid limits and bad purchases
Footprint before model name: What matters is the actual underside of your optic. “Micro Red Dot” alone says nothing about the fit. According to UTG, RDM-20GL is designed for Docter/Venom/Noblex. Glock G44 is excluded. Use only the specified #6-48 screws; the wrong thread or incorrect screw length can damage the optic or mounting.
Technical data with practical interpretation


Compatibility Glock Double Stack according to manufacturer; Glock G44 excluded. This is the first fit check before purchase.


Optic footprint Docter / Venom / Noblex. Do not confuse with RMR, ACRO, or Aimpoint Micro.


Saddle height 0.15 inch / approx. 3.8 mm. This deliberately keeps the optic line low.


Material 6061-T6 aluminum, matte black anodized. Lightweight and corrosion-resistant in normal use.


Screws Included #6-48 T10 Torx. UTG specifies about 12 in-lb for the optic screws.


Dimensions / weight approx. 46.7 × 28 × 4.3 mm; approx. 13 g. Compact adapter instead of an additional tall base.


Scope of delivery
RDM-20GL mount, Glock dovetail insert, #6-48 T10 Torx screws in specified lengths, and T10 Torx tool. Optic and backup sights are not included.
Safe mounting and use
Mount only on an unloaded firearm and according to manufacturer instructions. Check for a firm fit before the first shooting, then check point of impact and recheck the screws after the first stress cycles. If unsure about the dovetail fit or screw length, have it professionally mounted.
FAQ
Does a Trijicon RMR fit? No. RDM-20GL is designed for Docter/Venom/Noblex footprint. Other mounts exist for RMR.
Does the slide need milling? No. The mount fits into the existing rear sight dovetail slot.
Is the original rear sight retained? No. This mount uses that dovetail position.
Does the Glock G44 fit? No, UTG explicitly excludes the G44 with hybrid steel/polymer slide.

Black Raptor · Avoid bad purchases
The RDM-20GL is a clean test and training solution if Glock model and Docter footprint really match. Those looking for RMR or maximum duty robustness should not overlook adapter logic.