Should we include this in our maintenance program?

[johnk]

Boyd Allen, prominent US shooter posted this several years back on a local forum, but thinks that it bears repeating:

Some years ago, I was at a match at Visalia, when one of the fellows that was a regular from Southern California, was having scope problems. Based on his usual performance, and the groups that he had just shot, that was the consensus among his shooting buddies. Someone offered him a spare scope, which he declined, and it was at that point that I asked him if he had tried "exercising" his turrets. He asked me what I meant, and I explained that it involved noting his turrets' settings and then running them to their limits several times, and then back to where they had been. Obviously this would also require re sighting the rifle before it could be shot with confidence. The scope was a 36X Weaver that had previously given good service. Having an open mind, and little to loose, he tried the procedure. It worked, and he went on to win a yardage with the same scope. My scope adjustments hardly get touched, and when they do, the movement is within a very short range, and this is probably the case for most shooters. I got the idea from an article in Precision Shooting. The author had compared the accuracy of tracking of new scopes with that of the same scopes after they had had their turrets run to their limits many times. Evidently the running in was beneficial. Tracking was improved. Perhaps the mating surfaces were smoothed and/or some lubricant (if there is any) redistributed, or some minute crud moved out of the way. I have no idea. My only advice would be to be cautious about getting carried away and to approach the ends of travel with some care.

[williada]

Yes, Yes, Yes. Something that should be done regularly. Too often the scope setup is neglected. That includes Lock-tighting screws, lapping scope rings and bedding scope rail. Some actually bed the scope in the rings so an optical centre will maximise the sighting. Likewise, a barrel that is not fitted straight in the vertical plane will give different zeros because the barrel and the scope point in different directions.

A good test of your scope at 140 yards is to shoot a rectangle. That is, wind 15 points right of zero fire a group, wind 15 points down and fire a group, wind 15 points left and fire a group and wind 15 points up and fire a group. Your scope is ok if you hit the same point of impact as when you started.

Backlash becomes a problem with some people's scopes if they are not exercised as John suggests. Knowing this, and it very much applies to coached shooting, if I wind the scope as a coach, I wind past the desired correction then back to it then give the signal to fire as the backlash problem is more common than you think. Good one John. David.

[jasmay]

I have done this from time to time John, Stephen Lazarus ponted this out to me in my early days of target shooting, I believe it to be beneficial..

[KHGS]

Boyd Allen, prominent US shooter posted this several years back on a local forum, but thinks that it bears repeating:

Some years ago, I was at a match at Visalia, when one of the fellows that was a regular from Southern California, was having scope problems. Based on his usual performance, and the groups that he had just shot, that was the consensus among his shooting buddies. Someone offered him a spare scope, which he declined, and it was at that point that I asked him if he had tried "exercising" his turrets. He asked me what I meant, and I explained that it involved noting his turrets' settings and then running them to their limits several times, and then back to where they had been. Obviously this would also require re sighting the rifle before it could be shot with confidence. The scope was a 36X Weaver that had previously given good service. Having an open mind, and little to loose, he tried the procedure. It worked, and he went on to win a yardage with the same scope. My scope adjustments hardly get touched, and when they do, the movement is within a very short range, and this is probably the case for most shooters. I got the idea from an article in Precision Shooting. The author had compared the accuracy of tracking of new scopes with that of the same scopes after they had had their turrets run to their limits many times. Evidently the running in was beneficial. Tracking was improved. Perhaps the mating surfaces were smoothed and/or some lubricant (if there is any) redistributed, or some minute crud moved out of the way. I have no idea. My only advice would be to be cautious about getting carried away and to approach the ends of travel with some care.

As a matter of fact something In do religiously is wind my scopes to 1000yds & rest them there at the end of the shoot. I use a set of digital callipers to measure this setting & I record it in my range records book. My scopes stay rested in at this setting from week to week. If you keep good records & use the callipers you will never get "lost". I see it as "easing springs", most shooters look at me with a blank look when I try to explain what I do & why. If you have an engineering background & understand anything about springs it will make sense. It is my observation that scopes will usually become unreliable at long range when you need them to be at their best, I believe this is due to "spring set" particularly on scopes that are used mostly at 3,5 & 600yds.
Keith H.

[johnk]

Naturally, when I posted this thread, I sent Boyd a link to it. He's added the following:

In one of the subsequent posts on that thread a fellow mentioned taking a turret setting past the intended setting and coming back to it to eliminate backlash. I cannot post on that forum so I leave it up to you to make a correction. My information on this came from Dick Thomas, the late owner of Premier Reticles. The issue is not primarily backlash in the turret itself. The problem is the erector tube precisely following the contact surfaces of the turret. Turrets act as "jacking screws" that move the erector tube against the balancing force of some sort of spring or springs. On the old scopes and some of the new ones this was a single leaf spring that was tied down to the scopes main tube on one end and bearing against the erector tube on the other, pushing it against the ends of the turrets. If an adjustment involves pushing the erector tube toward the spring, there is no particular problem, but if the adjustment is in the opposite direction, the whole system depends on the spring being able to overcome the sliding friction of the spring on the tube, and the friction in the pivot system that is generally at the back of the erector tube, just in front of the retile (in a second focal plane scope). If the spring is not strong enough, the tube may not follow the retracting turret end which would cause the scope not to track properly. To recap, if the turret has RH thread one should make adjustments in the clockwise direction by going directly to the intended setting because in that case the erector tube is being pushed by the turrets. On the other hand, when making a counterclockwise adjustment there is the possibility that the spring may not be strong enough to make the erector tube follow the retracting turret ends, and in those cases only, shooters are well advised to go past the intended setting by a few clicks, and come to it in the clockwise direction. Short version, always finish clockwise. It has been my experience that shooters are often confused on this matter and do what the poster recommended, go past and come back for all adjustments.

Hopefully you can understand why this is not desirable.

I will make one correction to your introduction to my post. I am not a prominent shooter, but rather one who enjoys the subject in all of its technical details, and occasionally writes a little on related matters. Have a good one.

Regarding the last sentence, I feel that Boyd is making light of his contribution towards precision shooting over some period of time. I can only assume that he is actually a Canadian.

[williada]

John, thanks to Boyd for pointing that out. We never stop learning. Something I carried over from TR days. Certainly knew there was an issue there. David.