Brownells Window Slide Assembly For Glock 43 With Holosun 407K Cut

The Brownells Window Slide Assembly for Glock 43 with Holosun 407K cut gives you a factory-quality upgrade path for your EDC pistol or a complete custom-build starting point. This slide is machined from 416 stainless steel billet and finished in black Nitride, built to Glock factory specifications so it accepts standard G43 frames and compatible aftermarket alternatives. Whether you're running a stock G43 or starting from a bare frame, this slide drops in and works with factory and aftermarket barrels and internals without modification.

The defining feature here is the pre-cut mounting slot for Holosun 407K reflex sights—a popular choice for compact pistol optics that keeps your sight picture clean and your profile low. Not ready to mount a red dot yet? Brownells includes a lightweight polymer cover plate to keep the slot protected and the slide looking finished. Standard-height front and rear iron sights come installed, so you can use them as primaries or as reliable backups once you dial in an optic. The window cutout in the top of the slide serves dual purposes: it lets ambient air flow to cool the barrel during heavy shooting, and if you've upgraded to a uniquely finished or ported barrel, the window showcases it while keeping your pistol slender enough to fit standard G43 holsters.

Manipulation is solid thanks to wide, shallow cocking serrations at the rear and a matching front set that makes press-checks and manipulation from any position easy. The slide arrives complete with a recoil spring assembly, so assembly is straightforward—though note that Brownells recommends a channel liner for installation (sold separately). This is purpose-built for shooters who want a refined compact carry gun without the bulk and cost of custom gunsmithing.

Key Features

• Pre-cut mounting slot for Holosun 407K reflex sights (low-profile, integral design)
• Machined from 416 stainless steel billet with black Nitride finish for durability and corrosion resistance
• Factory-spec internal dimensions accept Glock 43 factory and compatible aftermarket frames, barrels, and components
• Window cutout in top slide for barrel cooling and aesthetic customization
• Factory front and rear iron sights installed and ready
• Wide, shallow rear cocking serrations and front press-check serrations for confident manipulation
• Includes optic cover plate and recoil spring assembly
• Compact profile maintains compatibility with standard G43 holsters

Specifications

Frequently Asked Questions

What red dot sights will this slide accept, and what else do I need?

The slide is pre-cut for Holosun 407K footprint optics and mounts them directly without adapters. If you want to run a different reflex sight footprint—such as RMR—adapter plates are available separately. Brownells includes a polymer cover plate if you're not ready to mount an optic immediately.

Will this slide work with my factory Glock 43 frame?

Yes. The slide is machined to Glock factory specifications inside and fits standard Glock 43 frames as well as compatible aftermarket frames. It accepts factory and aftermarket barrels and internal parts without modification.

Does the window cutout affect holster compatibility?

No. The window is cut in the top of the slide, so the pistol remains compact and slender enough to fit holsters designed for the standard Glock 43.

What tools or additional parts do I need to install this slide?

Brownells recommends installing a channel liner during assembly. The liner is a press fit and requires a separate tool (Brownells part #777100017 is recommended for this task). The slide ships with the recoil spring assembly and cover plate, so you have those components on hand.