PolarStar Gas Stock Adapter for Elite Force MP5K Airsoft Guns

Compact HPA & Stock Conversion for the MP5K Platform

The PolarStar Gas Stock Adapter for the Elite Force MP5K is a precision-engineered upgrade designed for airsoft players who want to unlock maximum modularity from their MP5K platform. Whether you’re building a self-contained HPA CQB setup, running a remote line, or simply upgrading to an AR-style buffer tube stock, this adapter delivers rock-solid performance in a true drop-in design.

CNC-Machined Strength & Precision Fit

Machined from a solid block of 6061 aluminum, this adapter offers exceptional durability without unnecessary weight. The anodized finish improves corrosion resistance and provides a clean, professional appearance that pairs perfectly with high-end HPA and AEG builds. PolarStar’s tight tolerances ensure a precise fit and long-term reliability under aggressive field use.

Drop-In Installation – No Gearbox Modification

Designed primarily for the Elite Force MP5K (CYMA OEM), the adapter installs using the factory body pins, making it completely non-invasive and reversible. No gearbox modification is required, and the adapter does not interfere with internal components.

It is also compatible with Tokyo Marui and Galaxy MP5K models, requiring only minor receiver fitting, making it a versatile option across multiple MP5K variants.

UGS & CGS Compatible for Line-Free HPA Builds

Featuring internal 1-3/16-16 threads, the adapter directly supports PolarStar UGS (Universal Gas Stock) and CGS (Compact Gas Stock) systems. This allows players to create a fully contained HPA or CO₂-powered MP5K without the need for a remote air line—ideal for tight indoor CQB environments where mobility and clean ergonomics matter most.

Running a line-free setup reduces snag points, improves weapon handling, and delivers a cleaner overall profile.

Milspec Buffer Tube Compatibility

Not running a gas stock? No problem.

This adapter also functions as a standard Milspec buffer tube adapter, allowing you to install AR-style stocks when using a remote air line or even when running the MP5K as an AEG. Compatibility with real steel Milspec buffer tubes opens the door to countless stock options, letting you dial in your preferred length of pull and cheek weld.

Anti-Rotation Lock & Sling Plate Support

To ensure maximum stability, the adapter includes a built-in 10-32 anti-rotation set screw that tightens against the underside of the buffer tube. This keeps the stock perfectly indexed and eliminates unwanted movement during aggressive play.

Additionally, the design supports real steel Milspec receiver end plates, allowing you to use your preferred sling mount configuration for single-point or two-point sling setups.

Key Features

• CNC-machined 6061 aluminum construction

• Anodized finish for durability and corrosion resistance

• Direct drop-in fit for Elite Force MP5K (CYMA OEM)

• Compatible with Tokyo Marui & Galaxy MP5K (minor fitting required)

• Accepts PolarStar UGS & CGS gas stock systems

• Milspec buffer tube compatible

• Anti-rotation set screw for rock-solid stock alignment

• Supports real steel Milspec sling end plates

Manufacturer

PolarStar