Bisley 30mm Two Piece Medium Economy Mount By Richter Optik 
 
After you have chosen a top quality scope mount you will find one of the first decisions you need to make is, how high do I need the scope mount to be ? As a general rule it is best to keep your scopes objective lens as close to the barrel as possible so therefore low or medium height scope mounts are a popular choice.
 
The advantage of this is that the flight path of your bullet or pellet will be close to the crosshairs of the scope so hold under / holdover will be minimised. However sometimes your eye line will be above the centreline of the scope so you will need to use higher scope mounts to bring the centreline of your rifle scope in line with your eye line. Common reasons for this are due to your rifle having a high cheek piece but the actual height of your eye level will be different from person to person as we are all built differently. Rifles with an adjustable cheek piece are quite an advantage when trying to find the ideal head position which is both comfortable and in line with the centre of your rifle scope.
 
Another factor that can affect the height of scope mount you need is the thickness or overall diameter of your rifle barrel. A larger diameter barrel will effectively reduce the clearance between the barrel and the bottom of your riflescope objective lens. For example the same rifle and scope may need medium height scope mounts if the standard diameter barrel is fitted but if the heavy varmint barrel is fitted then the best scope mounts maybe the high model. The make and model of riflescope also affects which height scope mounts / rings you need to use when mounting your scope. This is because some rifle scope manufacturers use thicker materials so the objective lens diameter can be the same i.e. 50mm but the overall diameter can vary.
 
Another factor is the thickness of your scope covers. It is fine to choose low or medium height scope mounts that mount your riflescope really close to barrel whilst maintaining a comfortable head position but what if you cant fit the protective covers to your scope ? Normally around 2mm is sufficient to allow for this but please remember aftermarket flip up scope covers are often thicker than the covers which are supplied with a scope.