Picatinny Ring Mount | 40 mm | Screw

This assembly is blued. Bluing, also known as black oxidizing, is a chemical surface treatment that provides a nice, matte black finish and a certain degree of corrosion protection. It is the most traditional surface treatment for firearm parts.

Bluing is less resistant than QPQ and requires a bit more care – a thin layer of oil after use in damp weather will keep the surface in good condition.

Installation is simple. The rings are attached to the Picatinny rail, and the scope is placed in the lower ring halves, after which the upper halves are tightened.

Manufacturer's recommendation:
• Torque for ring screws (top, M3.5): 1.8–2.0 Nm
• Torque for mounting against rail (M4): 2.0–2.5 Nm
• Ensure the scope is level and has correct eye relief before final tightening

A torque wrench is necessary for proper installation. Overtightening can damage the scope tube.

Scope mounting:Read the guide here

This mount is made of steel. Steel is the classic choice and offers high rigidity and wear resistance. The material can withstand repeated assembly and disassembly without deforming the contact surfaces.

Steel is heavier than aluminum, but for a ring mount, the weight difference is practically minimal.

Rusan is a Croatian manufacturer with over 30 years of experience in precision mounts for rifles. All products are manufactured in-house on modern CNC machines from solid material – without casting or metal injection. Rusan is known for tight tolerances, high repeatability, and an unusually wide range of rings, mounts, and adapters for night vision optics.

Read more about Rusan here: Rusan

See all products from Rusan: Rusan Collection

The mounting height of rings is typically given as BH (Base Height) — measured from the top of the picatinny rail to the bottom of the scope tube (the saddle).

When calculating the total height (Center Height), you must add the radius of the scope tube to the BH measurement. For a 30 mm tube, the radius is 15 mm. For a 34 mm tube, the radius is 17 mm.

Formula: Center Height = BH + r

Remember that the picatinny rail itself raises the mounting point (typically 5-10 mm depending on the rifle model). This means that you can often choose a lower ring than you would otherwise need.

Rule of thumb: Choose the lowest ring height that still allows free passage between the scope's objective and the barrel. A lower mount provides better balance and a more natural sight picture.

These rings have an internal diameter of 40 mm and are suitable for binoculars with 40 mm tubes.

Always check your binocular's tube diameter before purchasing – it can be found in the binocular's specifications or easily measured with a caliper.