HELP understanding scope hold over and adjustments

[jamesbern]

So I have a question I hope you can answer and i'm trying to understand.

Lets say I sight in and get my 100 yard zero. Do you reset the turrets so they both read zero after you sight in at 100 yards or do you leave them at whatever numbers they are at?

Now lets say I want to shoot at a 400 yard target. Wind is from 2 o'clock at 4mph all the info for the conditions are in my ballistic caculator.

This is the range card that it feeds out:

Now, because of wind from the right I read that as moving -.5mrads or half a mil to the right so i'm turning counter clockwise if you look at the scope from the right side.

Then I see -2.8 mrads under mRads for DROP. When I see the negative symbol I think I need to go down, but it really wants me to go up in elevation, correct? Looking at my scope, actually, I see how you need to turn counter clockwise to go 1mrad, 2mrad, etc so I think I understand the reason for the negative now.

If i'm zeroed at 600 yards there is a positive number for adjustment as the target gets closer which means I would turn the turrent clockwise.

Now with that said, I should, after making the correct changes be able to hold on the target and hit, right?

My last question is if I didn't want to adjust the scope at all, I should be able to hold half a mil towards the right and 2.8 mRads above the target. right? That would mean the center of the cross hairs would be a half mil to the right and 2.8 mils above the target. At least that is how I understand it. For targets where I would need to dial more mils in than the recticle shows I would either have to do it totally in the turrets or partially and then hold over the rest of the way.

Please tell me i'm understanding this.

 

[Win308]

Re: HELP understanding scope hold over and adjustments

I am just learning myself, but I believe that when you sight in, you want to set your turrets to zero to make it easier to come back to your 100yd adjustment after changing their positions to adjust for different distances and wind conditions.

 

[Win308]

Re: HELP understanding scope hold over and adjustments

Common sense would say that if you are shooting farther than you zeroed, you would hold higher and into the direction that the wind is coming.

 

[jamesbern]

Re: HELP understanding scope hold over and adjustments

It makes sense to me, I just want an experienced shooter to confirm my understanding of it and make sure i'm explaining it correctly.

I just shot my first bolt action rifle last weekend so i'm very new to this.

 

[Petey]

Re: HELP understanding scope hold over and adjustments

Yup, you've got it.

If you zero at 100 yards, you'll want to reset both windage and elevation turrets to zero. This will make dialing solutions from you program much easier as the software will assume you're starting from zeroed turrets anyway.

The #1 rule with turrets regarding up/down and right/left is that those are telling you which direction you want the bullet impact to go. For your first example (400yd shot w/ 100yd zero and wind going right-to-left), intuitively you know that you need to bring the bullet impact UP and RIGHT. Those are the directions you'll need to turn the turrets based on the numbers coming back to you from your ballistics program. If the turrets aren't marked U/D or L/R, an easy way to remember this (for almost all scopes, anyway) is the old 'righty tighty, lefty loosy' we all learned about screw threads. Just pretend the turret itself represents the bullet impact; if you want to bring the bullet up, turning the turret like you'd loosen a screw will bring it up.

Your particular program is telling you the actual trajectory of the bullet from your zero, so that's why the negative signs are causing you to doubt yourself a bit. Some programs will tell you the correction, and might say U2.8 rather than the -2.8 in your program. Getting very familiar with the software is critical.

You're spot-on with the hold-offs explanation.

 

[jamesbern]

Re: HELP understanding scope hold over and adjustments

Petey - Thank you very much! It is nice to be able to read this stuff and start to get an understanding of it all. Two days ago this was very overwhelming.

 

[cookietheswede]

Re: HELP understanding scope hold over and adjustments

I would try to teach yourself to hold for wind. The wind is never a constant and it gets annoying making scope adjustments during "swirling" or "gusty" days. And it never fails that once you dial your wind in it will stop or change direction.

Just a quick check your scope adjustments are in Mrad and not MOA right?

Have fun and keep shooting it will be second nature after a while.

 

[MontanaKid]

Re: HELP understanding scope hold over and adjustments

Is that the KAC bullet flight app? I have it too, but I haven't put it to the test. Can anybody confirm the apps accuracy?

 

[adam1122]

Re: HELP understanding scope hold over and adjustments

Pretty good grasp of things considering you just got behind the bolt gun for the first time or two. You can get a kick ass ballistics calc. that you seem to have one and then all you need to know is the distance to the target and the wind...the calculator will spit out the elevation and windage for you. The more accurate you are with your wind reading and atmospherics and the more you know about the specific round you are shooting the more accurate you will be at any range.

You can google the subject on either a Mil or MOA scope and it will help you understand the principles of both of them.

Welcome to the shooting world and good luck with it. Ask the hide if you need help - the guys on here know their stuff.

Oh, and JBM ballistics calc. is generally the best you can get without buying a handheld pda-like computer

 

[adam1122]

Re: HELP understanding scope hold over and adjustments

Pretty good grasp of things considering you just got behind the bolt gun for the first time or two. You can get a kick ass ballistics calc. that you seem to have one and then all you need to know is the distance to the target and the wind...the calculator will spit out the elevation and windage for you. The more accurate you are with your wind reading and atmospherics and the more you know about the specific round you are shooting the more accurate you will be at any range.

You can google the subject on either a Mil or MOA scope and it will help you understand the principles of both of them.

Welcome to the shooting world and good luck with it. Ask the hide if you need help - the guys on here know their stuff.

Oh, and JBM ballistics calc. is generally the best you can get without buying a handheld pda-like computer

 

[AtOne]

Re: HELP understanding scope hold over and adjustments

Remember that the wind reading that your phone app is getting may not be the conditions for where your shooting from, as its pulling data from the nearest weather station.

You can hold assuming your scope is FFP if it's SFP then it will only work at one magnification setting.

 

[verdugo60]

Re: HELP understanding scope hold over and adjustments

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Win308</div><div class="ubbcode-body">I am just learning myself, but I believe that when you sight in, you want to set your turrets to zero to make it easier to come back to your 100yd adjustment after changing their positions to adjust for different distances and wind conditions. </div></div>

First of all...this.

 

[verdugo60]

Re: HELP understanding scope hold over and adjustments

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Petey</div><div class="ubbcode-body">Yup, you've got it.

If you zero at 100 yards, you'll want to reset both windage and elevation turrets to zero. This will make dialing solutions from you program much easier as the software will assume you're starting from zeroed turrets anyway.

The #1 rule with turrets regarding up/down and right/left is that those are telling you which direction you want the bullet impact to go. For your first example (400yd shot w/ 100yd zero and wind going right-to-left), intuitively you know that you need to bring the bullet impact UP and RIGHT. Those are the directions you'll need to turn the turrets based on the numbers coming back to you from your ballistics program. If the turrets aren't marked U/D or L/R, an easy way to remember this (for almost all scopes, anyway) is the old 'righty tighty, lefty loosy' we all learned about screw threads. Just pretend the turret itself represents the bullet impact; if you want to bring the bullet up, turning the turret like you'd loosen a screw will bring it up.

Your particular program is telling you the actual trajectory of the bullet from your zero, so that's why the negative signs are causing you to doubt yourself a bit. Some programs will tell you the correction, and might say U2.8 rather than the -2.8 in your program. Getting very familiar with the software is critical.

You're spot-on with the hold-offs explanation. </div></div>

Petey summed it up very well, good job. As for dialing for wind vs. holding off it is a matter of experience and preference and the conditions. At my last match I was shooting a very light bullet compared to others in my squad. (223 DMR style rifle with 68 grain match bullets.) On the last string the wind blew one way, dropped to nothing and then went the other way. With the format of the match, I had a little bit of time after my shot to gauge the wind for the next and dial. Even with my light bullet/caliber combo, for whatever reason I was hitting when the guys with better ballistics were not. It may not have been ALL because of dialing vs holding off, but it did allow me to focus on my fundamentals rather than my hold off. So, again depending on circumstances and your style you might want to dial for wind.

Also, I don't know what phone you have but the "Shooter" app for Android mobiles is as good as JBM (or better for my uses) and costs $10. Practice judging wind for yourself, even when you have the technology. Batteries fail, weather and cell stations go down, but if you have printed dope on or near your rifle at all times and can gauge wind you will still hit.

 

[jamesbern]

Re: HELP understanding scope hold over and adjustments

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AtOne</div><div class="ubbcode-body">Remember that the wind reading that your phone app is getting may not be the conditions for where your shooting from, as its pulling data from the nearest weather station.

You can hold assuming your scope is FFP if it's SFP then it will only work at one magnification setting. </div></div>

Thanks. I actually picked up a Kestrel Weather station so I will be taking my readings from that to use in accordance with the ballistic program. I got it out again last weekend and shot a 5 shot group at 100 yards that hasn't been measured, but probably grouped a .750" or so.

I just joined a range that allows use of the 400 yard rifle range so at least i'll get to practice at some distance now.