Arisaka Defense Offset Plate, Holosun 407K & 507K For 1.5''- 1.8'' Scope Mount

The Arisaka Defense Offset Plate for Holosun 407K & 507K is a precision mounting solution that lets you run a compact red dot sight alongside your scope without the guesswork. Designed for scope mounts in the 1.5" to 1.8" height range, this offset plate gives you a clean, co-witnessed setup that keeps your optic centered over the bore even when you cant the rifle to use the red dot. If you're building a rifle that needs both magnified glass and a fast close-quarters sight, this plate makes the combination work.

Arisaka's offset system is built around modularity. The plate can be positioned at either 35 or 45 degrees—the 35-degree angle sits closer to slimmer scopes, while 45 degrees clears wider turrets and larger optics. The base itself is reversible, so you can mount on either side of the gun. It's all CNC machined from 6061-T6 aluminum and hard-coat anodized to Mil-Spec, so it'll stand up to field work and stays reliable when it matters.

At 1.9 ounces, the mount keeps your setup lean. The base occupies three Picatinny slots on a standard AR-platform top rail and sits 0.180" above the rail surface. Included drivers (IP20 and IP27 Torx Plus bits) are everything you need to secure it. If your optics collection grows or you upgrade down the road, Arisaka sells bases and plates separately, so you're not locked into a single configuration.

Key Features

• 35 or 45-degree offset positioning for red dot placement
• Maintains 1/3 co-witness height with optic centered over bore
• Reversible base for left or right mounting
• Fits Holosun 407K and 507K reflex sights
• Compatible with 1.5" to 1.8" scope mount heights
• 6061-T6 aluminum construction with Mil-Spec hard-coat anodize
• Lightweight at 1.9 oz (without optic)
• Includes mounting drivers

Specifications

Frequently Asked Questions

What offset angles does this plate offer?

The Arisaka offset plate provides two position options: 35 degrees, which brings the sight closer to slimmer scopes, and 45 degrees, which clears wider turrets and larger, higher-magnification optics. You choose based on your scope and layout.

Can I use this on a left-handed rifle?

Yes. The base and optic plate are reversible, allowing installation on either the left or right side of the rifle.

What's included with the mount?

Each base comes with IP20 and IP27 Torx Plus bit drivers for installation and adjustment.

What height scope mounts is this plate designed for?

This standard-height plate is designed for scope mounts in the 1.5" to 1.8" height range. If you have a taller scope mount (1.9" to 2.2"), you would need a different plate height.