Collimator Holosun HS503-G ACSS

Holosun HS503-G ACSS Vulcan is a compact closed red dot sight featuring a motion-activated wake system, ACSS CQB reticle, and a 1/3 co-witness mount.

Designed for long guns such as AR15 rifles and semi-automatic shotguns.

Lightweight Design

The housing is made of 6061-T6 aluminum with precision milling. The device has a lightweight and durable construction weighing only 138 g with the high mount. Holosun HS503-G ACSS Vulcan ensures “stable zero retention”, is parallax-free, and its optical system provides unlimited eye relief, making it suitable for sport rifles, AR rifles, and hunting firearms.

Optics

The Holosun HS503-G ACSS Vulcan uses multi-coated, anti-reflective lenses for high light transmission and a sharp, clear parallax-free image.

Electronics

The controller and LED are shock-resistant up to 1000 G, capable of handling firearm recoil and environmental conditions, ensuring stable performance on both sporting and hunting firearms.

Battery Saving System

Impressive runtime of up to 50,000 hours is achieved thanks to the motion sensor, which automatically shuts off the LED when idle and puts the device into sleep mode. Simply moving the firearm reactivates the dot.

BDC ACSS Vulcan Reticle

The ACSS Vulcan is Holosun’s proprietary reticle calibrated for 7.62 NATO and 5.56 NATO ballistics. The center features a thin chevron (inverted V) surrounded by a thicker horseshoe. Below the chevron is a dot grid for bullet drop compensation. This intuitive reticle excels at close-range dynamic shooting and medium-range precision. ACSS is a simple yet functional aiming system appreciated by beginners and experienced shooters worldwide.

Convenient Battery Mount

Many shooters value easy battery access. In the Holosun HS503-G, the battery is mounted on the side under a cap on the right side of the housing. This allows battery replacement without removing the sight from the firearm, unlike models with bottom-mounted batteries.

The package includes a high mount (1/3 co-witness) for Picatinny rails, suitable for rifles, and a low mount recommended for shotguns and AK-style rifles.