Scope Adjustment and Zeroing

[Madhatter]

Ah!! I get it so after zeroing at whatever range you would log the changes for change in distance and any windage for future use if those conditions are repeated?

[Rockhopper]

Well thats what I do. Some people can work out the number of minutes of angle difference for each range then translate that into the number of clicks but for some reason I just can't think that way!

We shoot unlimited sighters at 25,50 and 100 so i never record windage. We also shoot at 200,300 and 500 (with only five sighters allowed) and at 500 especially i just aim off if its windy as I get totally lost if i try and adjust the sight to compensate.

[rox]

there is little point taking any notice of the numbers, all you need to do it count the number of clicks and in which direction you are turning it

Couldn't disagree more.

Always work in absolute values. You (and others) can verify absolute values.

Winding up from <wherever the sight was left at> is making several assumptions - assumptions that could see you outside the safety envelope.

Ah!! I get it so after zeroing at whatever range you would log the changes for change in distance and any windage for future use if those conditions are repeated?

Not quite. Again, record absolute values. The change in elevation required from 500 to 600 is not the same as the change from 900 to 1000.

You should record, for a specific ammunition/rifle/sight combination, the absolute elevation required for a specific distance, and the wind zero. Hopefully your wind zero will be almost the same at different distances, but it isn't necessarily so. If you shoot a slow/deliberate style (like F Class or TR in pairs or threes), you may also record shot by shot settings and fall of shot, and in some cases plot graphs corrected for those adjustments (there is much debate on the merit of these, particularly the wind graph). I'll follow-up with a plot sheet complete with graphs to give you an idea.

Another mistake I see regulrly is when people are given 2 sighters and adjust on the first (usually cold barrel) shot. Not until the second round goes down will you have any idea how close your MPI was. If you adjust on a bad shot, you compound the error.

Slightly disagree with this, especially if sighters are 'convertible'. With a little experience, I know what kind of group to expect. If my 1st shot is more than 1/2 that diameter away from the centre, I'll make a correction. That improves my chances of not needing to correct on the second (and improves my chances of 'converting' the second, if applicable). Even without conversions, I'd rather be starting a scoring string without having just moved the sights, given the choice. I can correct for the adjustment and 'see' the group size and centre (as if the adjustment wasn't made) either mentally or on a plot sheet. Admittedly I've never had much issue with cold bore shots being out of the group - presumably due to using stiff match barrels. The first shot out of a clean bore at long range, however, certainly has to be taken with a big pinch of salt!

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[Maggot]

Ah!! I get it so after zeroing at whatever range you would log the changes for change in distance and any windage for future use if those conditions are repeated?

Yep. Known as elevation or numbers on the rifle. As Rockhopper points out this can be easier said than done with some scopes.

My Elcans are battle scopes and are not really designed to have elevation set. They have a very good ballistic ret, but this only works with SS109 stanag ammunition (so it has a predictable trajectory) and you are trying to hit a fairly large item. Our bulls come down to the size of a cricket ball so something a bit more precise is needed (and it can be a pain trying to locate then hold the correct point of aim). I heard of a technique used by the Canadian Army where they wind on the elevation and aim dead centre. This makes my life easier as my loads are match not service so are a bit slower anyway. I just took a paint pen with me and as I confirmed each elevation, I dotted the wheel with paint (it is just a notched elevation wheel that locks). I then coloured them in a logical sequence R/O/Y/G/B/V 100-600 and white (3 clicks under 100 for standing supported at 100). Simple, repeatable, needs no numbers. I can get 100-600 in before I go one full turn. My Steiner has loads of elevation and is zero stop but again I will as likely colour code it. As regards wind it takes ages to get an idea, but initially, if in doubt, aim at the into wind edge of the target. A hit somewhere is better than a miss in the sand.

[Maggot]

Another mistake I see regulrly is when people are given 2 sighters and adjust on the first (usually cold barrel) shot. Not until the second round goes down will you have any idea how close your MPI was. If you adjust on a bad shot, you compound the error.

Slightly disagree with this, especially if sighters are 'convertible'. With a little experience, I know what kind of group to expect. If my 1st shot is more than 1/2 that diameter away from the centre, I'll make a correction. That improves my chances of not needing to correct on the second (and improves my chances of 'converting' the second, if applicable). Even without conversions, I'd rather be starting a scoring string without having just moved the sights, given the choice. I can correct for the adjustment and 'see' the group size and centre (as if the adjustment wasn't made) either mentally or on a plot sheet. Admittedly I've never had much issue with cold bore shots being out of the group - presumably due to using stiff match barrels. The first shot out of a clean bore at long range, however, certainly has to be taken with a big pinch of salt!

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Horses for courses Bob. I have just seen so many people shoot a pants first sighter, adjust on it and put themselves further in the crap than if they had taken both. In my world sighters are not convertible in any event, so use them to the best advantage (2 confirms 1). Actually in some matches we dont get any, and we dont get plot sheets either so its what you see is what you get. Then its usually into a 50 round match with those being your only sighters at the longest range. Different strokes mate. The practical optic shooters may disagree.

[Madhatter]

Whilst watching this thread unfold hoping that one day I will actually understand what is being discussed but grateful all the same, I am currently reading "the long range shooting handbook" Ryan M. Cleckner in which he says "it is the responsibility of the individual to find out how his/her scope works, what the turrets do and what happens when they are moved. I started this thread under the illusion the there was an answer that I would understand however, I have realised that I am trying to find an answer to a problem I do not fully understand "at the moment" I appreciate all the comments and note that there are differing opinions even amongst you experienced contributors, I shall continue to build my knowledge and through the advice of you guys or gals hopefully it will start to sink in

[Rockhopper]

there is little point taking any notice of the numbers, all you need to do it count the number of clicks and in which direction you are turning it

Couldn't disagree more.

Always work in absolute values. You (and others) can verify absolute values.

Winding up from <wherever the sight was left at> is making several assumptions - assumptions that could see you outside the safety envelope.

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So how does that work if your elevation adjustment is more than one whole turn of the dial?

[rox]

So how does that work if your elevation adjustment is more than one whole turn of the dial?

Read markings that exist for that purpose (if present), or start from a known fixed point, like first '0' encountered when winding up from the minimum elevation; count revolutions x mins/mils per rev, plus mins/mils/clicks/graduations for the final (partial) revolution.

[rox]

Just to illustrate the concept, here's an example of a completed plot sheet (you should see a scan below). These are only applicable for certain types of shooting, of course, and there are many ways to do things.

The plot sheet records absolute elevation and wind settings for each shot, fall of shot, score, corrected wind and elevation graphs, and other data about the shoot.

This was quite a challenging wind shoot at 1000 yards - only 6 out of 42 shooters broke 70 (ex 75), and only 2 of us who were on the difficult detail (the other a Queen's prize winner). The wind wasn't especially strong, and this shows that difficulty isn't necessarily related to strength.

The wind zero is noted to be 1/4 of a minute right, and that didn't need to be changed throughout the shoot. Shot A was fired on 2 minutes right wind, shot B on zero (which would have read 1/4 right on the sights due to the wind zero), shot 2 was fired on one and one quarter minutes right etc, ending on 5 minutes left.

The graphs show you *corrected* elevation and wind, i.e. with sight changes removed so you see the true grouping of the shoot. In both cases the position of each blob shows you the exact setting you needed to have on the sights in order for the shot to strike dead centre. In the case of the elevation graph this helps to visualise the formation and development of the group, and you can easily read-off the group centre and put that value on the sights - often more weight is placed on the last 3 shots as the group progresses. In this case the elevation group opened-up significantly in the latter half of the shoot, caused mainly by firing very quickly indeed due to the speed of wind changes; the longer you take over firing the shot, the more opportunity you give the wind to be different from the value you've just decided-upon and put on the sights, so sacrificing a little shot precision to 'get the shot away' quickly can really pay off.

The wind graph is arguably of much less value. It isn't showing you just *your* group, because of that extra variable - the wind itself. The graph is therefore a historic tool and is of very limited use in predicting the future. I rarely plot either graph, much of these were completed after the shoot. Most top-level wind coaches argue that your time is better spent watching the wind indicators and feedback, rather than head-down, plotting historical information.

[Madhatter]

OMG!! my brain has just imploded I can only hope that one day I might understand the meaning of all your data