Verifying the true value of your scope clicks

Southcape · Post by **Southcape** » Tue Jan 10, 2012 10:29 am

http://bulletin.accurateshooter.com/2011/12/verifying-the-true-value-of-your-scope-clicks/

johnk · Post by **johnk** » Tue Jan 10, 2012 2:36 pm

I'm happy when my scopes move the inch without the .047 per nominal MOA. Considering the accuracy of my (our?) wind judgement, I don't see it matters a bit. If ot comes to that, I'm happy if the spotter disc isn't perforated precisely in the centre, or that the marker places the patch eccentric to the bullet hole. The semaphore disc can be rotated off the alignment shown in the SSRs, as if it matters.

Of course, those strange Asian scopes sometimes have interesting (or challenging, or unique) calibration.

Woody_rod · Post by **Woody_rod** » Tue Jan 10, 2012 7:54 pm

johnk wrote:I'm happy when my scopes move the inch without the .047 per nominal MOA. Considering the accuracy of my (our?) wind judgement, I don't see it matters a bit. If ot comes to that, I'm happy if the spotter disc isn't perforated precisely in the centre, or that the marker places the patch eccentric to the bullet hole. The semaphore disc can be rotated off the alignment shown in the SSRs, as if it matters.

Of course, those strange Asian scopes sometimes have interesting (or challenging, or unique) calibration.

John, do you mean 1.047" = 1 MOA? Agreed on odd scope calibrations....we have one that moves around 1.3 MOA per indicated graduation.

johnk · Post by **johnk** » Tue Jan 10, 2012 8:05 pm

Nah, Woody, if it moves an inch, I'm good. I figure 1.2 mm isn't worth worrying about when your looking at the incremental change.

Woody_rod · Post by **Woody_rod** » Tue Jan 10, 2012 8:13 pm

True enough, so you mean the additional 0.47" - makes sense now. An inch is close enough.............

Woody_rod · Post by **Woody_rod** » Tue Jan 10, 2012 8:25 pm

I just read the article in the link. Might pay us to go through this process and see what we find. If I remember, will post the results here.

If people are wondering how the MOA is worked out, it is done like this:

100 yards = 300 feet
300 feet multiplied by 12 = 3600
3600 x 2 (to give diameter) x pi (3.142)
22,622.4 divided by 360 (to give degrees)
62.83 divided by 60 (to give minutes)
= 1.04733 (recurring)

DaveMc · Post by **DaveMc** » Wed Jan 11, 2012 11:20 am

Actually Rod (and I don't like to pick but as I know you will handle it well here goes - and all done in good humour).

Unless you have a curved target with the radius of curve the same as distance it is actually = 3600*tan (1/60) = 1.04719752166006.
Whoops hold the fort I assume you actually have the target mounted in the middle of your target line, not off to the side so a flat target mounted in middle but perfectly perpendicular to line of sight would actually be = 2*3600* tan(1/120) = 1.04719754381246 (now to be that accurate you will have to measure your distance pretty well with some sophisticated gear and make sure target is perfectly perpendicular in a horizontal and vertical plane.

Nah - come to think of it I won't argue with you over 0.00013578952087" inches or thereabouts - in fact I will go with John and say an inch is close enough.

JannieSA · Post by **JannieSA** » Fri Jan 13, 2012 9:25 pm

Dave

Will it be then OK if I use 25mm?

JOKESSS :!:

DaveMc · Post by **DaveMc** » Sun Jan 15, 2012 6:14 am

Sure Jannie but it always helps to have lots of decimal places :lol:

Barry Davies · Post by **Barry Davies** » Sun Jan 15, 2012 7:38 am

An error of 0.047" per 100 yards = 0.47" at 1000yards. The finest sight graduation is 1/8 MOA ( assuming it is true ) = 1.31" at 1000 yds.
One would have to have rather exceptional skills to be worrying about this?
Of course 1.31" is worth having under any circumstances but I can only think of one where you might really worry about it, and at my stage in life an inch or so here or there is of little benefit. :lol:

Barry

Norm · Post by **Norm** » Sun Jan 15, 2012 10:59 am

Consider this.
A shooter sights in his rifle at 100 yards. Assumes that the click values are in a fraction of an inch. They are actually in fractions of a MOA.
The shooter is using a .308 and is starting off at a 1000 yard shoot.

He dials up some 32 iphy as per his ballistic program and misses the bull by some 1.5 MOA.

ned kelly · Post by **ned kelly** » Sun Jan 15, 2012 4:45 pm

G'Day All,
given the variable effects from all the envoirmental conditions, I've simply worked on "actual" clicks and a record book of each barrel, adjustments from your "zero point", for each rifle range (takes into account different altitudes etc) and the different distances I've shot over, as a consequence, I dont see the point of knowing the value of the clicks and I suspect they change as you run through the full range of adjustment anyway.

The main concern is to know your scope is tracking properly and repeatable.

food for thought

Cheerio Ned

TOM · Post by **TOM** » Sun Jan 15, 2012 6:49 pm

I have never seen the fun in counting 'clicks', although ive seen a heap of people doing it, I then scratch my head wondering why and leave them to it while I go and count in MOA, heck, the smart cookies even put numbers on the turret for ya. One thing for sure Ned is jotting your elevations down for each distance, This will most likely work out 'pretty' right at your home range on a daily basis, but rarely at another , even from morning to afternoon with the changes in atmosphere it can and probably will change a touch but it's gonna get you a good hit no matter where your shooting. You get 2 sighters you can cut out, make the most of them.

ned kelly · Post by **ned kelly** » Sun Jan 15, 2012 7:57 pm

G'day all,
Tom, sorry it wasn't real clear, I keep a record for each range I shoot on, Werribee, Castlemaine, Bendigo and for each distance I shoot at these facilities.
Makes it easy.
Anyway, a simple wind change is worth a lot more than any variation in click values! Just so long as I'm on paper and roughly near the centre, as I hold off for all my shooting once the elevation is good.
Cheerio Ned