Home » Categories » Multiple Categories

Scope Mounting - What Mounts Height Do I Need?

Getting the Right Height is Key - The Lower the Better

Set your rifle solidly upright.  Ideally, clamp it into one of those cleaning stands or a vice.  Make sure the rifle is horizontal.  Take your scope and position it on top of the action with the ocular lens (eyepiece) the correct distance from the back of the stock to give you the eye relief you need.  Average will be 280mm. You cannot sit it directly on top of the action yet because the objective lens hits the barrel.  You need spacers under the tube to lift it clear of the barrel.  Anything will do but  ideal is the fore mentioned loose change.  Coins are convenient and come in different thicknesses.  Put a stack in front of the adjusting turret and a stack behind.  Adjust the number of coins until the objective lens is clear of the barrel, measure the height of the coin stack and you have the height you need for your mount.

A couple of points to note.  Some actions are a different height front and rear so you need to use different stack heights to keep the scope parallel to the bolt or bore line.  If your rifle already has a Picatinny rail fitted this will already be correct and you just need to sit the stack on top of that.

Scope Mounting Instructions

Usually you Can Calculate X by the following method:

Scope Objective Lens: L (Example 50mm +wall thickness = 54mm outer diameter)

Scope Mid Tube: M (Example 30mm)

Minimum BH Needed: X

Formula: (1/2 x L) - (1/2 x M) = X

In Practise: (1/2 x 54mm) - (1/2 x 30mm) = 12mm BH


Scope mounts in Europe have a stated height for each component, known as the ‘BH’.  If measuring from the top of a Picatinny rail you only need the height from the top of the rail to the underside of the scope tube to give you the ring height.  If measuring from the top of the action you may need to add mount component parts together.  For example, if you measure from the top of the action a height of 14mm and plan to mount a Picatinny rail you need to subtract the rail thickness to give you the ring height you need.  A typical rail will be 6mm so your ring height will need to be over 8mm otherwise the objective lens will touch the barrel.  If you use lens covers you need to add a bit otherwise you will not be able to get them on.

2 (1)
Article Rating (1 Votes)
Rate this article
  • Icon PDFExport to PDF
  • Icon MS-WordExport to MS Word
Attachments Attachments
There are no attachments for this article.
Comments Comments
There are no comments for this article. Be the first to post a comment.
Related Articles RSS Feed
Mounting Rail scopes on Optilock bases (Tikka and Sako)
Viewed 38980 times since Tue, Sep 11, 2012
Steyr-Mannlicher
Viewed 3264 times since Mon, Jan 6, 2014
Picatinny or Weaver Rail and Bases Mounting Procedure
Viewed 10630 times since Thu, Jun 23, 2016
Scope Mounting Instructions - Getting the Correct Height for Picatinny Rail & Rings
Viewed 22221 times since Wed, Mar 5, 2014
Rear Extended Picatinny Rails for Night Vision
Viewed 2155 times since Thu, Nov 2, 2017
Rifle Hole Spacing for Fitting Picatinny Rails or Bases
Viewed 32122 times since Wed, Mar 5, 2014
Sako 75 Picatinny Rail Fitting Problems
Viewed 39898 times since Wed, Mar 5, 2014
Recknagel Catalogue 7
Viewed 3580 times since Mon, Aug 20, 2012
Mounting Multiple Scopes on to One Rifle without Losing Zero
Viewed 6559 times since Thu, Jul 10, 2014
Anschutz Rifle Measurements for Mounting Scopes
Viewed 41368 times since Wed, Jul 9, 2014