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Zeroing at 100m .5cm off

Posted: Fri Aug 14, 2020 10:31 am
by Rem260
Hi Guys
Using a mil scope with 0.1 mil adjustments.
If you try to zero at 100m's and your rounds group .5cm off centre. How do you true for dead centre as 1 click will take you .5cm in the opposite direction. Not much of a problem at that distance but at 500m it will be 2.5 cm off if I am doing my calculations correctly. Which will probably affect any ballistic calculator.
Does this indicate something wrong somewhere? Or is it the limitation of the coarser mil system?
3 round groupings where 0.234 and .287 MOA

Re: Zeroing at 100m .5cm off

Posted: Fri Aug 14, 2020 2:41 pm
by snayperskaya
What scope is it, what calibre are you shooting and what rifle is it?.The type of shooting you are doing will, in my opinion also have a bearing......for example if you are shooting Fig11's on a MOD range I'd say jobs a good 'un and not worry about 5mm at 100m

Re: Zeroing at 100m .5cm off

Posted: Fri Aug 14, 2020 3:58 pm
by Sim G
You’re really that good to be worried by 1 inch at 546 yards?

That’s not supposed to sound as flippant or sarcastic as it sounds. Are you sure you’re not chasing something which is not of real consequence?

Or is it the maths and theory that is of more interest, that but I do appreciate.

An am I missing the point. Go 1 click the other way...

Re: Zeroing at 100m .5cm off

Posted: Fri Aug 14, 2020 5:40 pm
by poll007
From a purely mechanical standpoint from your description the only way to get the scope zeroed in that situation would be by moving the scope itself.

In reality I wouldn't imagine it to be an issue, but in theory you could slightly loosen and retighten the scope rings to shift the reticle relative to the target-though you would need to then rezero and hope it now lines up with one of your 0.1mil increments

I suppose it being windage or elevation thats off would make a difference.

Can i ask what setup you are using to achieve such accuracy?

Re: Zeroing at 100m .5cm off

Posted: Fri Aug 14, 2020 5:52 pm
by Ovenpaa
This is one of the issues with cm/clicks, in effect each click is just under half an inch at 100 yards. I would say try a windage adjustable scope base or shim the scope. The PMII on my Accuracy International is around 3,0mm right on a still day at 100m. Or a slightly over an inch at 1000 yards, luckily I have so many more things to consider at this distance and it never crosses my mind to worry about the initial error.

Have you considered a 1/8th Minute scope? Of course it may still end up being 1.6mm off zero at 100........

Re: Zeroing at 100m .5cm off

Posted: Fri Aug 14, 2020 7:32 pm
by Rem260
snayperskaya
Its a Rem 260 and a IOR Crusader. Shooting long distance
Sim G
No its not that I am that good and it is more for the calculation side of things. Especially at say 1110 yards the ballistics calculator could say 1.5mils with 8mph wind but if that is based on being dead centre. The actual could be an extra 2+ clicks which would miss the v ring. Causing you to chase the ring either side. Not knowing if its the wind or the extra clicks.
poll007
That was my initial thoughts but thought I would ask the question from more knowledgeable shooters.
Set up is Savage target action 30" Krieger barrel, Dolphin Stock, Tier 1 Bipod.
Ovenpaa
As I said its more for the understanding of the mechanics behind things and if there is something I can do to improve without going full OCD.

I am happy with my set up in general and am always willing to try new things and listen to others more experienced than I. Which is not that difficult.