TILTED MOUNTS are necessary when shooting at very long distances. We generally recommend as little tilt as possible as large amounts of tilt really may have a negative impact on the quality of the sight picture. In most cases 6-9 MIL (20-30 MOA) will have no negative impact on picture quality while still providing greater available adjustment range for long-range shooting.
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 elevation adjustment of 26 MIL (93 MOA,) you should, therefore, choose a mount 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 an oval picture when shooting at close targets, 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.
Please note that using a degree of tilt that is more than half of the scope’s elevation adjustment will make it impossible to zero your rifle at 100!
For a great Tilting Mount, we recommend the Spuhr ISMS series available here: https://www.opticswarehouse.co.uk/brand/spuhr/
Note: Same applies on all One-Piece Scope Mounts.