Sphur ISMS SP-3601 30mm Medium (30mm) 20.6 MOA Picatinny One-Piece Mount
Sphur ISMS SP-3601 30mm Medium (30mm) 20.6 MOA Picatinny One-Piece Mount
The Spuhr ISMS (Ideal Scope Mounting System) is an extremely sturdy scope mount that is machined from one piece solid billet, in 7075 T651 aluminium with no joins or joints which that can become weak overtime. This completely unique lightweight design of the Spuhr ISMS mount provides the platform for a rock solid picatinny style mounting system that will allow you to easily mount accessories and keep clear visibility of the scope turrets with minimal movement. This feature packed mount system from Spuhr really does make it the Ideal Scope Mounting System. A Built-in level is also found in the base of the one piece mount and a 45-degree split of the rings provides unobstructed view of the turret knobs.
Durability
A Spuhr ISMS Mount System will prevent damage on a scope due to flexing during heavy recoil or rough handling. The snipers rifle and the spotter’s carbine can have the same mount, enabling the use of the same or shared equipment and accessories.
Scope rotation
Spuhr ISMS Mount System has an innovative solution for indexing the rotation of the scope, using the included tool/gauge to index the scope correctly to the mount and gun. This is very important since if the scope is not properly indexed there will be an unintended lateral shift of the point of impact whenever the elevation is adjusted.
Mounting placements
Traditionally lasers have been mounted on the forend of the rifle, a solution with drawbacks. For the same reasons you don’t want your barrel to touch the forend you don ́t want the sights to be mounted on the forend. Sphur ISMS mounting systems have up to seven interfaces for accessories, and the laser can easily be attached to the scope mount, providing the advantage of undisturbed laser and having the weight close to the centre of the gun instead of forward.
Tilt
Spuhr ISMS Mounts can be delivered in various tilts. The tilt is clearly engraved on the mount, in both MIL and MOA.
Accessible and readable dials
Spuhr ISMS rings are cut at 45 degrees instead of horizontaly, providing several advantages; the screws holding the parts together are not obscuring the knobs, thus the shooter can quickly determine the settings of the knobs. The Spuhr ISMS also gives the shooter a horizontal reference line helping the shooter subconsciously to avoid canting the rifle to the side.
The rings have index marks on the top and right side, making low knobs more easily readable.
Accessories
Provides use of various accessories such as angle cosine indicator (ACI), back up sights, lasers, illuminators, night vision mounts etc. with a minimized ”footprint”. With traditional mounts this can only be achieved if there is sufficient space on the middle tube for additional rings, which there rarely is. The ”Ideal Scope Mount System”™ have interface surfaces directly on the mount, making it possible to mount accessories either by Picatinny rails or as direct interfaces. A selection of interfaces for popular accessories are available, and others can be made to customer specifications.
Level
The sight mount have a level included in the rear of the mount.
HOW TO CHOOSE THE RIGHT SPUHR ISMS MOUNT
We have the worlds most comprehensive line of tactical scope mounts; it currently spans about 45 different models of various heights, tilts, lenghts and ring dimensions.
Here is a short guide to help you choose the right one for your needs.
Picatinny or direct mount?
The first obvious question is if the mount should be a Picatinny mount or a direct attachment mount such as our line of ISMS mounts for Accuracy International, Sako TRG and Sauer SSG.
The main purpose for using a direct mount is to allow a stronger and lower positioning of the rifle scope. If there’s no need for Picatinny we generally recommend direct mounts on these rifles.
Tilt.
Tilted mounts are necessary when shooting at very long distances. We generally recommend as little tilt as possible as the tilt really does nothing to improve the picture quality. In most cases 6-9 MIL (20-30 MOA) will have no negative impact on picture quality while a greater tilt can lead to problems.
To allow for the greatest available range of adjustment choose a mount with a tilt that is half of the scope’s range of elevation
For example Schmidt & Bender 5-25×56 have a maximum 26 MIL (93 MOA) in elevation, then choose amount with 13 MIL (45 MOA) in tilt. Doing so assures that you are able to adjust the sight out to very long distances.
However when mounted in this extreme elevation it’s common to experience optical defects such as anoval picture etc
We therefore recommend that when fitting a large elevation scope (such as 26 MIL/93 MOA) on a .308 rifle that will only be used out to 1000 meters, to choose a 6 MIL/20 MOA tilt as it’s more than sufficient for that use.
Height
The height of a mount is always measured from the top of the rail to the center of the scope. In the case of a tilted mount the measurement is made at the rear of the mount.
Night vision/thermal compatible
When combining the scope with a clip-on system such as PVS22 or NSV 80 to name a few the height of the mount is not important. Also the instrument doesn’t have to be perfectlyin line with the scope.
If we have an offset of 10mm in height betwen the primary optic and the NV clip-on the change in point of impact will be 10 mm on 100 meters as well as 10 mm on 300 and 1000 meters; thus the point of impact change is fully parallell.
Therefore it’s often unneccesary to have extremely high mounts just to facilitate in-line mounting of a clip-on systems. Various systems allow varying degrees of angular difference. A common maximum angular difference is 2 degrees.
Please consult the manufacturer of the thermal device before you make expensive alterations to your gear.
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Sphur ISMS SP-4901 34mm Medium 31 MOA Picatinny One-Piece Mount Specifications
Picatinny mount for use on bolt action rifles
Rings: 30 mm
Tilt: 6 MIL/20.6 MOA
Height: 30 mm/1.18”
Length: 126 mm/4.96”
Weight: 237 g/8.4 oz
Interfaces: 7 sets
EAN: 7340150700133
Sphur ISMS SP-4901 34mm Medium 31 MOA Picatinny One-Piece Mount Features
The SP-3601 is designed for use on rifles with MIL-STD-1913 or STANAG 4694 rails, and is especially suitable for bolt action rifles with 1-piece Picatinny rails. The SP-3601 will fit most 30 mm scope tubes except for scopes with extended erector housings, such as the US Optics TPAL/EREK.
Background
The Ideal Scope Mount System (ISMS) originated in a customer request to help develop a way to mount the optics to a rifle in such a way that the rings did not obscure the turrets of the scope.With traditional mounting solutions the user has a choice between obscuring either the elevation or the windage adjustments (and in some cases both!)
The first trick was to make the cut of the rings diagonal rather than horizontal or vertical, thus putting the “fat” part of the rings offset from the scope turrets – a solution we ended up patenting. Then we made the sides of the rings straight as to further minimize the profile.
We also added indexing marks to the rear ring to draw the eye to the adjustment reading.We machine the mounts from 7075 T651 billet aluminum, as this material is lightweight and extremely strong, even outperforming construction steel in several aspects.
Our fasteners are 12.9 Grade steel with zincnickel corrosion resistance, and they come pre-waxed to ensure proper torque values. The second request was to find a way to attach accessories to the scope mount without having to replace parts of the mount or having to re-zero the scope in between changes – it was also requested that the accessories zero should have a high degree of repeatability.
The resulting solution is the Spuhr Interface, which can be found on all our mounts, and most of our weapon upgrade kits. The resulting product was the first ever scope mounting system - a system where the mount is not just merely there to attach the primary optics to the rifle, but to also hold accessories that may not fit elsewhere on the rifle (especially on a bolt action rifle that only has the Picatinny scope base or a dovetail on the receiver).
An added bonus is the bubble level installed into the rear of the mount and the 10-degree “wedge” we include with all our mounts to make installation as easy as possible by aligning the bottom of the erector housing of the scope to the bridge of the mount, thus aligning the reticle with bubble level and the mount body.
10-degree leveling wedge
This simple tool fits in a 10-degree slot on the mount while mounting the scope and works against the bottom of the scope to ensure a perfectly level scope.
4 numbered and indexed mounting torx heads
Built in level
Even the slightest variance in how the mount is attached to a weapon can alter the point of impact. To resolve this, the ISMS has numbered screw holes so you can attach the mount the same way each time. The amount of torque applied to the mount can also cause unwanted variance so Spuhr has placed index marks on the screw head so you can put the exact same amount of torque on your mount no matter how often you remove the mount.
With a quick glance from your left eye you can get an instant check of your level without leaving your shooting position. The built in level is always protected in the rear of the mount and is not a risk of shifting or being broken off on the move.
Accessory interface :
Every mount consist of 7-8 mounting interfaces where you can attach nearly anything. The interface consists of two threaded M4 holes that are depressed in a conical hole to perfectly fit the individual attachment interfaces (sold separately) with absolutely no play in the joint.