Ade from Optics Warehouse provides a detailed explanation of Spuhr's One-Piece Scope Mounts coding system.

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We have a fair few customers say they are unfamiliar with the terminology and descriptions of Spuhr's One-Piece Mounts, and furthermore, unsure on which Mount is best for their Shooting needs.

So, with this in mind, we have broken down Spuhr's terminology and provided basic explanations on what they mean. 

Please note, some models may be available in different heights, MOA, variants, and only in selected combinations.

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The initial letters identify the type/firearm/rail the mount is designed for:

QDP - Quick Detachable mount Picatinny
SA - Scope mount Accuracy International (11mm dovetail)
SP - Scope mount Picatinny
SS - Scope mount Sauer (for Sauer SSG and STR rifles)
ST - Scope mount TRG (17 mm dovetail)
SR - Scope Rings (separate rings for Picatinny rail)

The first digit identifies tube diameter:

3 - 30 mm tube
4 - 34 mm tube
5 - 35 mm tube
6 - 36 mm tube
7 - 40 mm tube

The second digit identifies tilt:

0 - 0 tilt/flat 0 moa
3 - 3 MIL/10.3 MOA
6 - 6 MIL/20.6 MOA
7 - 7 MIL/24 MOA tilt
8 - 13 MIL/44.4 MOA
9 - 9 MIL/31 MOA

The third digit (if other than 0) is for special versions:

1 - Cantilever mount
2 - Extended cantilever mount
3 - Short rear top cover for the S&B Ultra Short
4 - Medium cantilever mount

The fourth digit identifies height:

1 - 30 mm / 1.18"
2 - 38 mm / 1.50"
4 - 48 mm / 1.73"
6 - 34 mm / 1.35" (except for on Cantilever mounts)
8 - 44 mm / 1.73"

B suffix

Some mounts feature a B suffix following the model number.
In the ISMS line, this indicates an extra-long mount for scopes with extended length erector housings, such as the U.S. Optics TPAL and the NightForce B.E.A.S.T.

Sizing info:

38mm is for mounting 56mm on flat tops.
Above 38mm heights are for flat tops and using in-line Night Vision attachments.
You can use 34mm heights for 50mm objectives for flat tops but May suffer from touching if a pair of flip-ups is used.
30mm heights are most Bolt Action Rifles, providing sufficient clearance for standard Bolt Actions with a Picatinny rail on them. 

[Data and Spec Info: https://spuhrwebshop.com/en/ ]

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To see our full range of Spuhr Mounting Systems, CLICK HERE.