Spuhr ISMS SP-4801C Ø34mm Tube 13 MIL (30mm High) Gen 3 Picatinny Scope Mount

• Rings: 34 mm
• Tilt: 13 MIL/44.4MOA
• Height: 30 mm/1.18”
• Length: 120 mm/4.72” (body), 130 mm/5.12” (OAL)
• Weight: 217 g/7.7 oz
• Interfaces: 7 sets

• Monolithic one‑piece construction - CNC‑machined from a single billet of aerospace‑grade aluminium to eliminate tolerance stacking, flex, and ring misalignment common in multi‑piece mounts.

• High‑rigidity structural geometry - Optimised cross‑section and material distribution provide exceptional torsional and vertical stiffness, maintaining optic alignment under heavy recoil and dynamic loading.

• Hard‑anodised surface treatment - Type III hard anodising delivers excellent abrasion resistance, corrosion protection, and a non‑reflective tactical finish.

• Diagonal ring split design - Improves load distribution around the scope tube while keeping elevation and windage turrets fully accessible, preventing obstruction during adjustment.

• Integrated scope levelling system - Built‑in bubble level allows the shooter to reference rifle cant and optic alignment directly on the mount for precise long‑range shooting.

• Multi‑axis accessory interface -  Machined mounting points on multiple faces of the mount support direct attachment of optical and electronic accessories without adding separate rails.

• Low‑profile accessory mounting - Keeps mounted devices close to the bore axis and centre of mass, preserving rifle balance and minimising parallax and offset errors.

• Precision‑cut recoil lugs and rail interface - Provides repeatable, slip‑free engagement with Picatinny rails for consistent return‑to‑zero performance.

• High‑strength fastener system - Torque‑optimised fasteners maintain clamping force under vibration and recoil, preventing optic movement or zero shift.

• Designed for extreme‑range precision - Engineered to support the mechanical and optical demands of ELR, PRS, and professional long‑range shooting platforms.

• Spuhr ISMS Gen 3 SP-4801C 34mm Medium (30mm) 44.4 MOA Picatinny One-Piece Mount
• Manual
• "Wedge" levelling key

How does extreme cant affect erector system centering for ultra‑long‑range shooting?

Large cant angles shift the mechanical zero significantly downward within the scope’s adjustment range, allowing maximum upward elevation travel. This keeps the erector assembly operating near its central position where spring forces remain balanced and tracking behavior is more predictable.

Can extreme cant improve tracking repeatability at long distances?

When the erector system operates closer to its mechanical center, adjustment forces remain more uniform across elevation changes. This reduces the likelihood of hysteresis or slight return-to-zero deviations after large adjustments.

Does extreme cant influence optical clarity at high elevation settings?

Scopes adjusted near their internal limits may use lens regions farther from the optical center. Using cant reduces required adjustment and keeps the optical path closer to its optimal alignment.

Can improper torque affect cant alignment accuracy?

Uneven rail screw torque can introduce slight angular deviation in the mount body. This alters the effective cant angle and changes the elevation relationship between optic and bore.

How does extreme cant affect zeroing procedures?

Zeroing typically occurs near the lower portion of the elevation adjustment range. This requires careful adjustment to avoid reaching the lower mechanical stop prematurely.

How does ring alignment affect precision at extreme ranges?

Small alignment errors produce larger angular deviations at long distances. Precise ring alignment ensures the optical axis remains parallel with the mount structure.

How does cant influence internal scope spring pressure?

Large upward adjustments compress erector springs unevenly in flat mounts. Cant reduces required adjustment and maintains more balanced spring compression.

Does mount placement affect elevation travel usage?

Forward or rearward placement does not change total elevation travel available. It only affects eye relief and shooting ergonomics.

Can excessive ring torque affect scope tracking?

Excessive torque can slightly deform the scope tube and increase friction in the erector mechanism. Increased friction may produce inconsistent adjustment increments.

Does temperature variation affect cant accuracy?

Uniform thermal expansion preserves the geometric relationship between rings and base. The cant angle remains mechanically unchanged across temperature variations.

Can extreme cant limit close-range zeroing?

Large cant angles reduce downward adjustment travel available. Extremely close zero distances may approach the lower mechanical limit of the scope.

How does the mount maintain alignment during repeated adjustments?

The monolithic structure prevents ring movement relative to the base. This ensures that scope adjustments occur within a stable mechanical reference frame.

What installation error most often affects ultra-long-range performance?

Uneven rail screw torque is the most common cause of angular misalignment. This changes the effective cant angle and reduces usable elevation consistency.