The Holosun 507K X2 is a micro red dot reflex sight designed by Holosun Technologies for subcompact pistols and concealed carry weapons. Launched as a miniaturized version of the popular 507 series, this model adopts the Shield RMSc mounting footprint, which has become the de facto standard for micro-optics on compact guns. Its Multi-Reticle system, Shake Awake technology, and featherweight of 28 grams make it one of the most popular choices for everyday wear.
History and Development of the Holosun 507K X2
The market for micro red dots for subcompact pistols has seen rapid expansion from 2018 onwards, driven by the increasing demand from everyday wearers looking to equip their compact weapons with sighting optics. Shield Sights had led the way with the RMS and RMSc, establishing a compact mounting footprint that would become an industry standard.
Holosun launched the original 507K to cater to this segment, and then the X2 version in 2020 with notable improvements: a Lock Mode preventing accidental setting changes, optimized electronics for better durability, and a redesigned solar panel. The 507K X2 has established itself as the benchmark in the segment thanks to its unbeatable feature-to-price ratio, offering the Multi-Reticle system and the Shake Awake at a fraction of the cost of direct competitors.
Technical Specifications
| Feature | Specification |
|---|---|
| Official designation | HS507K X2 |
| Country of Origin | China (Headquarters: United States) |
| Manufacturer | Holosun Technologies |
| Production years | 2020 – present |
| Lens type | Micro-open reflex viewfinder (open reflex) |
| 1x magnification | (without magnification) |
| MRS Reticle | : 2 MOA dot / 32 MOA circle / circle + dot |
| Light Source | (Red) |
| Light levels | 10 diurnal + 2 night vision compatible |
| Dimensions | 40.6 × 24.9 × 24.1 mm |
| Weight | 28.3 g (1.0 oz) |
| CR1632 Battery (Side Loading) | |
| Battery life | Up to 50,000 hours (lowest setting) |
| Water resistance | IP67 (immersion 1 m for 30 min) |
| Case Material | : Anodized 7075 T6 Aluminum |
| Windage/height adjustments | 0.5 MOA per click, ±30 MOA stroke |
| Shield | RMSc Mounting Footprint (K-footprint) |
Operation and Technical Particularities
The Holosun 507K X2 incorporates the brand’s flagship technologies in a considerably reduced format. The Multi-Reticle System (MRS) offers three selectable configurations: a 2 MOA point for accuracy, a 32 MOA circle for fast acquisition, or a combination of both. This versatility is particularly appreciated on compact pistols where fast target acquisition is paramount.
Shake Awake technology automatically puts the lens to sleep after a period of inactivity and instantly reactivates it at the slightest movement. This feature is essential for everyday wear, ensuring that the sight is always operational when the weapon is unsheathed, while preserving battery life.
The side battery drawer allows the CR1632 battery to be replaced without disassembling the optics, thus preserving the zero setting. The windage and height adjustments offer 0.5 MOA clicks, finer than on the 507C, for a precise fit despite the small size of the sight.
Unlike the 507C, which uses the RMR footprint, the 507K adopts the Shield RMSc footprint (also known as the K-footprint), which is more compact and suitable for the breech-blocks of subcompact pistols. This distinction is crucial when choosing a viewfinder.
Variants and Versions
The 507K X2 is available in a red version (HS507K X2) and a green version (HE507K-GR X2), the latter of which offers better contrast in certain light conditions. A special version with ACSS Vulcan reticle, developed with Primary Arms, replaces the 32 MOA circle with a chevron designed to make it easier to center the reticle in the window.
In the Holosun range, the 407K is a simplified version with a single point of 6 MOA (without Multi-Reticle), offered at a lower price. The EPS Carry is the closed evolution of the concept, with a sealed housing providing better lens protection.
Common Guns and Compatibility
The Holosun 507K X2 is compatible with all guns that offer an optical cutout in the Shield RMSc format. Among the most common models are the SIG Sauer P365 XL, the Glock 43X MOS, the Smith & Wesson M&P Shield Plus, the Springfield Hellcat, the Ruger MAX-9, and the CZ P-10 S. Most modern compact pistol manufacturers now offer “optics ready” versions that are compatible with this footprint.
Civil Possession in Switzerland
In Switzerland, the Holosun 507K X2 is an optical accessory freely available for purchase without a special license. As a sight, not a firearm, it does not fall under the Federal Weapons Act (Firearms Act). It can be purchased from specialist gunsmiths or Swiss online dealers and can be mounted on any handgun equipped with a mounting plate to the Shield RMSc standard. Its installation on a legally owned pistol does not require any additional authorization.
Conclusion
The Holosun 507K X2 has established itself as the go-to reference for micro red dots for subcompact pistols. By combining the Multi-Reticle system, the Shake Awake and a side battery drawer in a case weighing just 28 grams, it offers a feature set that is unmatched in its price class. Its compatibility with the Shield RMSc footprint, adopted by the majority of compact pistol manufacturers, makes it a universal choice for everyday wear and defensive shooting.
