How to Pick Good Rings/Mounts

Identify scope outer dimension

Check manufacturer website for outer diameter spec. Leupold and Vortex list nicely on their site. Nightforce is 9mm + objective lens (NX8 2.5-20×50 will be 59mm outer diameter. Some manufacturers list in overview sheet on the site or in manual. Some manufacturers do not list at all.

Identify rifle type out of 3 (AR pattern, bolt action with short rail, bolt action with full rail)

    1. AR Pattern is any AR15, AR10, SCAR, or similar rifle. These have many different names but most will look similar to these:

    2. Bolt action with short rail will cover many different models as well. Remington 700, Savage 11 or 110, Winchester 70, Howa, etc. Look for short section of picatinny rail above receiver, or no picatinny rail on receiver:

    3. Bolt action with full rail will be chassis style rifle like AI AX series, Cadex, Christensen MPR, Ruger Precision Rifle (RPR), etc. Even if picatinny rail is not long, usually these will have a handguard like an AR15, and an adjustable cheek piece.


    1. AR Pattern: no calculation needed. Recommend 1.5” cantilever scope mount in appropriate tube diameter. Vortex, Nightforce, and Spuhr make good options. Can go higher like 1.7” or 1.93” for LPVO.

    2. Bolt Action with short rail: Ring height = Scope outer diameter / 2 – 0.25 inches

    3. Bolt Action with full rail: Ring height = Scope outer diameter / 2 + 0.25 inches


    1. Leupold Mark 5HD 2-10x30mm (35mm) M5C3 Matte Front Focal Non-Illum TMR Riflescope 179702 mounted to Ruger American Ranch rifle

    a. Identify scope objective outer diameter = 1.6 inches

    b. Rifle type is bolt action with short rail

    c. Calculate: Scope ring height = 1.6 inches / 2 – 0.25 inches = 0.55 inches

    This height is lower than any 35mm rings that are offered, so we can go with the lowest size we can find.

    Answer: Seekins 35mm .95″ Low scope rings, 4 cap screw

    2. Trijicon Credo 1-8×28 FFP w/ Red/Green MRAD Segmented Circle 34mm Matte Black Riflescope 2900032 + Perun X16-16-GPR Rifle

    a. Identify scope objective outer diameter = 1.4 inches

    b. Rifle type is AR style

    c. Calculate: no calculation needed, 1.5” cantilever mount is good

    Answer: Trijicon 34mm 1.535″ Cantilever Mount w/Q-LOC AC22038

    by Tyler P