Picatinny Ring Mount | 40 mm | Screw

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.

This mount is made from steel. Steel is the classic choice and provides high stiffness and wear resistance. The material tolerates repeated mounting and disassembly without the contact surfaces deforming. Steel is heavier than aluminium, but for a ring mount the weight difference is minimal in practice.

This mount is blued. Bluing, also called black oxidation, is a chemical surface treatment that provides an attractive matte black finish and a 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.

This mount is manufactured to NATO STANAG 2324 / MIL-STD-1913 standard (Picatinny). That means it is compatible with all standard Picatinny mounts, rings and accessories – regardless of manufacturer. The Picatinny standard ensures you can freely mix rails, mounts and optics from different manufacturers. This gives you flexibility to upgrade or swap a scope without changing the mount. Picatinny vs. Weaver: Picatinny and Weaver look similar but are not the same. The difference is in the cross slots (recoil slots):
• Picatinny: Slots are 5.23 mm wide with a center spacing of 10.01 mm (fixed standard)
• Weaver: Slots are 4.57 mm wide with variable spacing (no fixed standard) A Weaver mount can in many cases be fitted to a Picatinny rail, because the Weaver tab is narrower than the Picatinny slot. But a Picatinny mount does NOT fit a Weaver rail – the tab is too wide. This mount is Picatinny and fits all rails manufactured to MIL-STD-1913 / STANAG 2324. See compatible mounts: Scope mounts

The mounting is simple. The rings attach to the Picatinny rail and the scope is placed in the lower ring halves, after which the top halves are tightened. Manufacturer's recommendation:
• Torque for ring screws (top, M3.5): 1.8–2.0 Nm
• Torque for attachment to rail (M4): 2.0–2.5 Nm
• Ensure the scope is level and has the correct eye relief before final tightening A torque wrench is required for proper installation. Over-torquing can damage the scope tube. Mounting the scope: Read the guide here

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 optics. Read more about Rusan here: Rusan See all products from Rusan: Rusan collection