Are you carrying a slim single-stack pistol and struggling to find a red dot that actually fits the slide? Most miniature red dot sights are sized for full-frame guns, and that leaves owners of the Glock 43X/48, SIG P365 family, Springfield Hellcat, and S&W Shield Plus family stuck looking for something smaller. The Holosun HS407K-X2 was built to solve exactly that problem.
In this review, we will walk you through the housing, the reticle, how it operates, and how it mounts to your handgun. We will also cover what other shooters say about it, then close with an honest recommendation on where the HS407K-X2 fits in your kit.
Holosun HS407K-X2 Review
The Holosun HS407K-X2 is an open-emitter subcompact micro red dot sight (MRDS) measuring 1.6 (in) x 0.98 (in) x 0.95 (in) and weighing just 1 oz. It runs a single 6 Minute of Angle (MOA) red dot from one A 3-volt lithium coin cell, 16mm across, holding about 120 to 140 mAh. It powers many micro and subcompact pistol optics that trade runtime for a smaller footprint.Full comparison → lithium coin battery, rated for 50,000 hours of battery life at setting 6, well over five years of intermittent use. Twelve brightness settings (10 daylight, 2 night vision compatible) cover everything from a bright range day to a dark room under night vision. The sight carries an A full IP code meaning dust-tight (first digit 6) plus temporary immersion to 1 meter for 30 minutes (second digit 7).Full comparison → water and dust rating, and Holosun lists the MSRP at $264.69, though it usually sells well below that on the street.
Holosun Technologies has built its reputation on putting feature-rich, reliable optics out at a reasonable price, and the 407K is its answer for shooters running slim carry pistols. That pedigree is the whole reason the HS407K-X2 exists: it takes Holosun’s familiar feature set (Shake Awake, long battery life, a tough aluminum chassis) and packs it into a body small enough to ride a single-stack slide.
Top Features of the Holosun HS407K-X2
Design
The defining design choice of the HS407K-X2 is its size. The housing is CNC-machined from A high-strength aerospace aluminum alloy (yield about 503 MPa / 73 ksi, roughly 1.8x that of 6061-T6) for only a few percent more weight. The go-to for duty and hard-use pistol optics, often forged.Full comparison → aluminum with a hard-anodized finish, measuring just 1.6 (in) x 0.98 (in) x 0.95 (in) and weighing only 1 oz. That makes it one of the smallest and lightest dots Holosun builds, and it is the whole point of the K series. This is an optic shaped to fit slim single-stack slides without overhanging the sides.
The low-profile, rounded body is built to carry. There are no sharp protrusions to snag on a holster or cover garment, and that matters a great deal on a gun meant to disappear under clothing. The X2 revision refined the button layout and added Lock Mode over the original 407K, tightening up the carry experience.
That carry focus is backed by a genuinely tough build. The HS407K-X2 carries an IP67 rating for water and dust ingress plus a 5000G vibration rating. Moisture, lint, and the daily recoil punishment a slide-mounted carry optic absorbs do not faze it. We think that combination of size and durability is what sets the K series apart from other subcompact dots on the market.
Reticle
The HS407K-X2 runs a single 6 Minute of Angle (MOA) red dot. I like 6 MOA for a defensive carry optic: it is big and bright, so the eye catches it fast during a draw. That is exactly what you want when speed of acquisition matters more than tiny-group precision. Reviewers report consistent hits on 6-inch plates out to 25 yards, which covers the realistic range of a defensive pistol.
There are twelve brightness settings in total. Ten are daylight settings, scaling up to a dot bright enough to stay visible against a bright sky, and two are night vision compatible for use with image intensifiers. The dot runs on Holosun’s efficient red Super LED, which is what makes the long runtime on a small battery possible.
Operation
Operation follows the familiar Holosun pattern. The ”+” and ”-” buttons cycle brightness, and the X2 adds Lock Mode, which disables the buttons so brightness cannot get bumped while you draw, holster, or manipulate the pistol. That is a meaningful upgrade for a carry optic.
That readiness is backed by Shake Awake, Holosun’s motion-activation system. The optic drops into a sleep state when it sits still and snaps back on to your last brightness the instant it senses movement, conserving the CR1632 battery without ever leaving you with a dark window. Pair that with the rated 50,000-hour battery life at setting 6, and you leave the dot on, change the battery on a calendar, and trust it to be ready. The side-loading battery tray means you swap the cell without removing the sight or losing your zero. Windage and elevation adjust in 1 MOA clicks with a +/-30 MOA travel range.
Mounting
The HS407K-X2 uses the Holosun K footprint, the same pattern as the Shield RMSc, rather than the common Trijicon RMR footprint. This is the one real planning consideration with the sight. The K cut is what lets the optic fit slim subcompact slides in the first place, but you need to confirm your pistol’s cut matches before you buy.
Some optics-ready carry guns ship with a native RMSc/K cut and accept the 407K directly. Others, a number of Glock 43X/48 MOS, Hellcat, and Shield Plus configurations among them, need an adapter plate. Confirm your specific slide before ordering, then zero the sight at your preferred distance and lock the screws to spec. In our experience, this is the step buyers skip and regret, so check the cut sheet twice before you order.
Details
Included with your purchase:
- Holosun HS407K-X2 sight
- Mounting screws (2x M4x12mm, 2x 6-32x7.4mm)
- Multi-tool
- Lens cleaning cloth
- User’s manual
- Warranty card
Customer Feedback
The Holosun HS407K-X2 is consistently rated among the best subcompact carry dots in its price range. Reviewers and owners single out the small footprint, the long battery life, and the value as the reasons to buy it. The most common note is simply to double-check footprint compatibility before purchase.
Carry Fit: Owners praise how the small, snag-free body rides a slim slide without printing or adding meaningful bulk.
Battery Life: Testers report many months of real-world use on a single CR1632, backing up the long rated runtime.
Value: The recurring theme is performance on par with optics costing twice as much.
Conclusion
The Holosun HS407K-X2 is one of the strongest subcompact pistol red dot sights on the market, and for a slim single-stack carry gun it is hard to beat at the price. The 1 oz K-sized housing, long battery life, Shake Awake, and added Lock Mode add up to a dot you can trust on an everyday carry pistol. You give up a larger window in trade for the K footprint, but for a dedicated carry optic, that is exactly the right call.
Alternate Options
If the 407K’s footprint or window size gives you pause, there are good alternatives at different points on the field. For a larger window and a multi-reticle system on a fuller-size slide, the Holosun 507C is an excellent step up. If you want an enclosed-emitter option on the same K/RMSc footprint, the Holosun EPS Carry is worth a look: it is a purpose-built subcompact carry pistol optic with a fully enclosed emitter, a closer match for slim-slide carry guns than any open-emitter design. If you would rather have the proven open-emitter standard on the RMR footprint, the Trijicon RMR remains a top-tier choice. Shooters who want a compact dot for a shotgun or backup-gun setup instead of a carry pistol should look at the Burris FastFire 3, and budget-minded buyers exploring the category for the first time may want to start with the Vortex Venom before stepping up to carry-grade gear.
