Spuhr ISMS ST-6401 Ø36mm Tube 4 MIL (30mm High) Sako TRG Scope Mount

SKU#ST-6401 Spuhr

Spuhr ISMS ST-6401 Ø36mm Tube 4 MIL (30mm High) Sako TRG Scope Mount

Name: Spuhr ISMS ST-6401 Ø36mm Tube 4 MIL (30mm High) Sako TRG Scope Mount
Brand: Spuhr
Price: 348.99 GBP
Availability: InStock

1 in stock

The Spuhr ISMS ST-6401 Ø36mm Scope Mount delivers exceptional strength, precision, and repeatability with its single-piece billet aluminium construction, providing a rock-solid platform for long-range shooting. Diagonally split rings allow unrestricted access to scope turrets, while the integrated levelling system and alignment wedge ensure perfect optic alignment during installation. With multiple accessory mounting interfaces and a hard-anodised aerospace-grade finish, this mount offers outstanding durability, modularity, and reliable performance in demanding tactical, competition, and hunting environments.

VIEW PRODUCT INFO / SPECS

Whilst we aim to dispatch in-stock items within 1 working day, please be aware that during busy periods dispatch of in-stock items may be delayed by up to 2 working days. Authorised UK Retailer

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Must-Have Additions for Your Order!

Spuhr Aluminium One-Piece 36mm Dovetail Rifle Scope Mount - 14MOA

THIS ITEM:

Spuhr ISMS ST-6401 Ø36mm Tube 4 MIL (30mm High) Sako TRG Scope Mount

£348.99

Spuhr A-0119 Bubble Level Assembly

£86.99

Spuhr Fix It Sticks

£119.95 Was £156.95

Total (3): £555.93

“The Ulfhednar 10cm Field Target Cordura Cushion is a great example of a simple accessory done properly. It provides the right amount of elevation and stability for field target shooting without being bulky or awkward to carry. The Cordura construction feels extremely durable, and the size makes it easy to position quickly when you’re under time pressure. If you shoot field target regularly and want something reliable that performs every time, this is a solid addition to your kit.”

Thomas, Sales and Product Specialist Accomplished HFT shooter offering optics and trade-in advice. Practical guidance based on years of competitive shooting.

Product Information FIND OUT MORE

DESCRIPTION

The Spuhr ISMS (Ideal Scope Mount System) is a high-performance mounting solution engineered for shooters who demand unmatched stability, precision, and modular versatility. Its single-piece, billet-machined aluminium construction provides exceptional rigidity, virtually eliminating flex under recoil and ensuring repeatable zero for long-range, tactical, and competition applications.

The system’s diagonally split rings give unobstructed access to elevation and windage turrets, allowing fast and precise adjustments without interference. An integrated levelling system and alignment wedge ensure the optic is perfectly level during setup, critical for extreme-range accuracy and consistent shot placement.

Multiple interface points along the mount allow secure attachment of a wide range of accessories, from lasers and rangefinders to backup optics and night-vision devices, without affecting rifle balance or ergonomics. Machined from aerospace-grade aluminium and finished with hard-anodised coating, the ISMS offers exceptional durability, corrosion resistance, and mechanical integrity under heavy recoil and field conditions.

With its combination of precision machining, modular functionality, and rock-solid strength, the Spuhr ISMS is designed to elevate any rifle platform, providing a foundation for accurate, repeatable, and adaptable long-range performance.

Ring Height - 30mm

SPECS

Ring Size 36 mm
Tilt 4 MIL / 14 MOA
Height 35 mm / 1.38"
Clearance 6 mm / 0.236" (from bottom of tube to bridge of mount body)
Length 126 mm / 4.96"
Weight 245 g / 8.6 oz
Interfaces 7 sets
Material 7075 T651 aluminium, hardcoat anodised
Screws Torx 20, zinc-nickel coated, pre-waxed
Included Adjustable recoil screw, 10° wedge levelling key, manual
Compatibility SAKO TRG-22, TRG-42, and Tikka T3x dovetail rifles
Objective Clearance Designed for scopes with up to 56 mm objective lenses

FEATURES

Direct dovetail fit for SAKO TRG-22, TRG-42 and Tikka T3x rifles, eliminating the need for additional rails.
Integrated bubble level at the rear of the mount to ensure correct rifle alignment and prevent canting errors.
Seven accessory interface points allowing attachment of over 40 different accessories from the Spuhr ISMS system.
Diagonally cut rings that improve visibility of elevation and windage turrets without compromising strength.
7075 T651 billet aluminium construction for maximum durability with reduced weight.
Hardcoat anodised finish for long-lasting surface protection.
Zinc-nickel coated Torx 20 screws that resist corrosion in all weather conditions.
Pre-waxed screws from the factory for consistent and secure torque application.
Adjustable recoil screw included for enhanced stability under heavy recoil.
10-degree wedge levelling key supplied for quick and precise scope alignment.
Designed for long-range performance, offering improved scope positioning and stability.

WHAT'S IN THE BOX

Spuhr Aluminium One-Piece 36mm Dovetail Rifle Scope Mount - 14MOA

FREQUENTLY ASKED QUESTION(S)

Why is a one-piece dovetail mount mechanically superior to split rings on a dovetail rail?
Split rings rely on the rail to align them; the ST-6401 does not. Because both rings are machined in the same fixture, their bores are perfectly coaxial. This prevents the scope tube from being forced into a bend when torqued down — a common cause of tracking errors.

How does the ST-6401 prevent scope tube ovalisation?
Spuhr machines the ring bores after anodizing so the internal diameter is exact. This ensures uniform radial pressure instead of point-loading, which can distort thin-wall 36 mm tubes and damage erector assemblies.

What role does the 14 MOA cant play in optical performance, not just ballistic reach?
By shifting the scope’s mechanical zero downward, the erector assembly operates closer to its optical center. This improves tracking linearity, minimizes optical distortion, and keeps parallax behavior more predictable at distance.

Does the ST-6401 reduce the need for shimming or bedding on dovetail rifles?
Yes. The mount’s base geometry is cut square to the ring axis, so the optic is already aligned to the dovetail’s reference plane, eliminating the need for corrective shims used on less precise mounts.

How does dovetail engagement differ from Picatinny recoil lugs?
Instead of a single recoil stop, the dovetail interface distributes recoil forces across the full length of the angled rail faces. This reduces micro-movement under recoil and prevents peening of a single lug.

Is the ST-6401 more tolerant of rail wear than separate rings?
Yes. Because it clamps across a long dovetail surface rather than two isolated points, wear on the rail is spread out, preserving alignment even after thousands of rounds.

How does this mount affect barrel harmonics?
The one-piece body resists torsional flex, so the scope mass does not oscillate independently of the action. This reduces tiny shifts in point-of-impact caused by optic mass reacting to barrel whip.

Can this mount support clip-on night-vision or thermal units?
Yes. The rigid, monolithic body keeps the scope’s optical axis stable relative to the bore, which is critical when using inline devices that depend on precise optical alignment.

Does the 14 MOA cant change how zeroing is performed?
Yes. Zeroing will occur with the elevation turret dialed slightly downward relative to mechanical center, which gives you more upward travel for long-range dialing while maintaining optical symmetry.

Why is this mount preferred on high-magnification 36 mm scopes?
Large-tube scopes have heavy erector assemblies. The ST-6401’s ring spacing and rigidity prevent tube flex that would otherwise degrade tracking and cause zero drift during recoil.

How does the ST-6401 handle temperature-induced zero shift?
The mount’s aluminum alloy is stress-relieved and anodized, reducing internal stresses that cause warping when temperatures swing from cold to hot firing conditions.

Why is ring spacing important on this model?
The ST-6401 spreads the rings far enough apart to stabilize long scope bodies, reducing bending moments on the tube when firing heavy recoiling cartridges.

DELIVERY & RETURNS

Our aim is to ensure that your order arrives with you as soon as possible and in the safest, most cost-effective means.

Please Note: Shipping charges may be subject to additional surcharges if out of area or over weight restrictions.

Please Note: DPD SHIPMENTS REQUIRE THE CUSTOMER TO SHOW A PIN CODE ON DELIVERY - READ MORE: HERE

COURIERS

We use DPD , RoyalMail, TNT and UPS courier services for all our orders whether dispatching to the UK or International. As soon as your order has been dispatched you will receive an email with your unique tracking number. We are unable to add delivery notes to your order regarding safe spaces or neighbour deliveries. If you require this service it can be arranged directly with the courier once the parcel is in their network.

IN-STORE ITEMS

These are items that we have in-stock and will be sent out for delivery as soon as possible. We aim to dispatch all orders within 1-2 working days, but during busy periods dispatch may be delayed by a day or so. If you would like to purchase the item in person then please call ahead to arrange an appointment: 01803 611 895.

PRE-ORDER ITEMS

These are usually items that are going to be out-of-stock for a number of weeks or are in short supply. By purchasing a Pre-Order Item you are in effect paying a deposit for your goods. As soon as the item is back in stock yours will be dispatched within 24 hours where possible. Please see individual product pages for current back-in-stock dates. In rare occasions, these dates can be changed by the manufacturers so we recommend staying in contact with Optics Warehouse depending on the product lead time.

INTERNATIONAL DELIVERY & TAXES

In addition to the above information If your delivery address is outside of the UK you may be subject to import duties and taxes, which are levied once a shipment reaches your country. Any such additional charges for customs clearance must be borne by you. You should note that customs policies vary widely from country to country. Optics Warehouse advises each customer to contact their local customs office for further information if they are in any way unsure of local duties or liabilities. Cross border shipments are subject to opening and inspection by customs authorities which means some packages may be opened and re-sealed.

NEED HELP?

If you require any further assistance, please call us on 01803 611 895 or email sales@opticswarehouse.co.uk

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A NOTE ABOUT DPD SHIPMENTS:

Please be advised that we have now introduced DPD Pins to all DPD orders from Optics Warehouse.
If your shipment is being sent from Optics Warehouse via DPD you will be sent a Pin Code that must be shown to the courier upon delivery.
The pincode is sent VIA email & TEXT message. A valid email address and mobile number must be provided at checkout. Emails will be sent from "Riviera House 3PL" - if you do not receive this email please check your junk or spam folders.
Please note that if you do not display your pin code to the courier driver upon delivery, you will not be able to have your item and you may need to schedule another delivery date to show a valid pin.
Please view the attached slides HERE for further information!

MOUNT SIZE GUIDE

Ring Height Calculator

This calculator works out the minimum ring height (base-to-centre) you should use, including a tolerance allowance.
Please note: All clearance calculations are based on mounts with 0 MOA. While MOA can be factored in, actual clearance may vary due to variables that can't always be accurately calculated. If you're considering an MOA mount and are unsure about the required height, we recommend contacting our sales team directly.

Scope Objective Outer Diameter (A)