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Nathan Foster

This post is to educate my readers (or remind my regular readers) at to the virtues of controlled tracking (e.g. Sightron) as opposed to spring resistance only tracking (e.g Leupold VX / Swaro etc).

I have previously talked (LR shooting book and here on the forums) about the issue of dialing up using a spring type turret. As the turret reaches its upper limits (dialed right up), the spring tension may become loose. Under these conditions, a scope, regardless of its pedigree (e.g Swaro) may for example shoot 3 to 5 MOA when dialed for a long shot. It therefore pays to test your scope at these upper settings. It may also pay to additionally test the upper setting yearly or bi-yearly.

To test the optic, work out how far you intend to shoot (max range). Lets say thats 1100 yards. Next, work out how much come up you need for this (lets say 35 MOA). Having sighted in and zeroed the rifle at 100 yards, dial up your 35 MOA and fire another group. Now here is the key - you need to check both the travel (was the scope true to clicks) AND THE GROUP SIZE. If the scope employs an opposing spring without any form of locking, the group may be large. If the group is large, the scope is useless for long range. If so, put the scope on a regular hunting rifle rather than a long range rig.

There is in addition to this, a further problem that concerns regular hunting rifles rather than long range rifles. If your scope bases or receiver are slightly out of line, it may force you to utilize a great deal of windage or elevation in order to zero your regular hunting rifle. If you have to dial right up or to the right to simply get the rifle zeroed at 100 yards, it may render the spring loose. As a reader relayed to me today:

My accuracy Saga's are over! It was the scope! I pulled the new 2.5x8x36mm Leupold and slammed on a Leupold 1x4x20mm I had since the 90’s that has always performed well on heavy recoiling rifles. Bam, my groups went from 6+MOA to under 1 MOA. It was then that I realized that the internal travel adjustment for the 2.5x8 Leupold was only 72 MOA and the 1x4 was 110 MOA. I had maxed out the elevation turret while zeroing it and because of the stress under recoil from the .35 Whelen, it would shift its POA every shot - hence the ridiculous groups.

Most of you know that I have some bias towards the high end SIII Sightrons. I am not completely biased but there are features of the SIII that I find highly useful. I hope this post helps to explain some of my reasoning.

To conclude, try to remember elevation and windage extremes as a potential issue when addressing accuracy problems. Some form of controlled tracking is generally more reliable than basic opposing spring tension within a turret (flat turret screw against a round erector tube).

Canted bases, canted rings (e.g Burris) and solid bases (which can be shimmed) with dovetailed windage adjustable rings can also be used to address various problems. Canting is not simply the domain of the long range rifle.