Holosun 507K
The Holosun 507K is the compact sibling of the 507C, engineered specifically for subcompact and micro-compact pistols where a full-size optic won’t fit. At 1.4 oz and using the Shield RMSc footprint, the 507K mounts directly on guns like the Sig Sauer P365, Springfield Armory Hellcat, and Glock 43X MOS without requiring an adapter plate—making it one of the most popular optics for everyday concealed carry. It delivers the same Solar Failsafe and multi-reticle system as the larger 507C in a housing purpose-built for micro pistols.
Read our full Holosun 507K Buying Guide ↓
Holosun 507K vs. 507C: Which One Does Your Pistol Need?
The 507K and 507C share the same Shield RMSc footprint, but the 507K has a smaller, lower-profile housing designed for micro-compact pistols. The 507C features a 32mm window and is better suited to full-size and compact guns (Glock 17/19, P320 full-size, M&P 2.0 compact). The 507K’s window is smaller at approximately 23mm, appropriate for a subcompact slide. If your pistol is a P365, Hellcat, Glock 43X, or similar micro-compact, choose the 507K. If it’s a full-size or standard compact, choose the 507C. The battery life and reticle options are the same on both.
What Pistols Are Compatible With the Holosun 507K?
The 507K uses the Shield RMSc footprint and is a direct-mount fit for several popular subcompacts. Factory-compatible pistols include the Sig Sauer P365 and P365XL (optic-ready slide required), Springfield Armory Hellcat and Hellcat Pro OSP, Glock 43X and 48 MOS, Smith & Wesson Shield Plus with optic cut, and Canik Mete MC9. Many micro-compact pistols now ship with the Shield RMSc cut as their standard optic-ready configuration, which has made the 507K one of the most widely compatible carry optics on the market. Always confirm your specific slide’s cut before purchasing.
507K Reticle Options: 6 MOA Dot or Circle-Dot?
The 507K ships with a 6 MOA red dot as the standard reticle option, or the Multi-Reticle System (MRS) version offering a 6 MOA dot, 32 MOA circle, or combined circle-dot. For a concealed carry pistol used primarily at defensive distances (3–15 yards), the 6 MOA dot or circle-dot provides fast target acquisition without the precision required at longer distances. The larger 6 MOA dot (vs. 2 MOA on the 507C) is intentional for subcompact carry guns—at typical defensive distances, a larger dot is faster to pick up under stress without sacrificing meaningful precision.
Holosun 507K Battery Life and Solar Failsafe
The 507K is rated at up to 50,000 hours of battery life on a CR1632 cell at medium brightness settings—that’s over five years of continuous operation. The Solar Failsafe panel on top of the housing provides supplemental or primary power in bright ambient light, further extending battery life during outdoor carry. The battery is accessed from the side of the housing (no need to remove the optic from the slide), and Shake Awake technology (on the X2 version) puts the optic in sleep mode when the pistol is holstered and wakes it instantly on movement. For a carry optic, these are genuinely practical advantages.
Is the Holosun 507K Durable Enough for Everyday Carry?
The 507K is built to IP67 waterproof and dustproof standards and is rated for shock and recoil on pistol slides including +P ammunition. Holosun has established a strong track record in law enforcement and competition use over several years, and the 507K specifically has seen wide adoption among concealed carry instructors and competitive shooters. For civilian everyday carry, it is more than durable enough. Those requiring mil-spec tested durability for duty use should consider the Trijicon RMR Type 2, which has more extensive military qualification testing behind it. See: Trijicon RMR.
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