Scope Zeroing for Multiple Loads

[ajandrs]

I've recently gone from mostly plinking FMJ's to varmint hunting and long range shooting. I'm still working on dialing in a good load for each purpose, but I only have the 1 rifle and scope to work with right now so separate rifles for each purpose is not yet an option. Rifle is an AR with WOA 18" SPR barrel with a Vortex 6-24 PST on top.

I figure there are 2 options, set a baseline scope zero and then zero in each load and simply write down the click values to achieve zero for a particular load. When I need to switch loads simply dial it back down to the baseline zero, then use the click value I previously wrote down to achieve zero for the other load. The second option would be to set the scope zero for the more commonly shot load, then zero off that for the other load, writing down the click value for that 2nd zero.

The 2nd option seems to make the most sense, but for some reason in my head the 1st option seems to be more simple or easier to deal with. Assuming the scope is properly mounted either method should work but was curious how you all do it.

 

[mahansm]

Depending on the scope, you should be able to set a zero marking on the scale under the adjustment knobs. I'd use that for the more commonly used loading and then record the number of clicks to get to the setting for the other loading. Be sure to check that the scope will return to the same point of impact after making the adjustment; some don't.

 

[Robert101]

Here is what I do:
I set the baseline to the most used load. Then record clicks to a second load. This way, I am set to my most utilized component.

In thinking a little more you may want to consider setting the base to the load you shoot the farthest. This way a load shot at a closer distance will have less sensitivity to scope adjustment.

I don't see much variation in my various load changes as I do with that darn wind. Wind is my biggest problem with mid-range shooting. Last outing the wind was reported at about 21 MPH. It felt like 30 and my shooting reflected it. I was out to 425 yards and my groups were horrible. Shooting from one canyon into another exaggerated it as well.

 

[farmerboy78]

Well I have a solution for you that I use myself. I use an app called Strelok Pro and it will compensate for you with only 1 zero. Zero for you mostly shot load and enter all that info in at the top of the cartridge list. And when you add subsequent loads there will be a spot for zero offset, which is the poi difference. The app will compensate for you and tell you what to dial.

 

[ajandrs]

Well I have a solution for you that I use myself. I use an app called Strelok Pro and it will compensate for you with only 1 zero. Zero for you mostly shot load and enter all that info in at the top of the cartridge list. And when you add subsequent loads there will be a spot for zero offset, which is the poi difference. The app will compensate for you and tell you what to dial.

Now that sounds pretty handy! A friend of mine just got that app the other day and was telling me about it but he must not have seen that feature yet. I've been using the geoballistic app lately but I'll have to check out strelok, thanks for the heads up!


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[Orcon]

I always range zero when changing loads. As long as you have a good DOPE for your loads you shouldn't have an issue with returning to zero. I shoot a handful of loads in several rifles but have a range card for each load. Weapon system familiarization, son.

 

[ajandrs]

I shoot a handful of loads in several rifles but have a range card for each load.

Yeah this is pretty much exactly what I was talking about in my OP. Thanks, pa!



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[jmr40]

I shoot 130-180 gr bullets in my 308 and 30-06. I just zero 165's at 100 yards. The 150's and 180's aren't off enough to matter at that range, not even at 200 yards. At longer ranges the difference is a lot less than most guys think. I don't change anything on the scope. I just have to remember there will be a very slight difference in drops at 300 yards or beyond. While the lighter bullets are faster, the heavier bullets better BC's help make up a lot of the difference.

With the 130 gr loads I see a much greater difference in not only elevation, but some difference in windage as well. If I'm shooting those, I re-zero the scope and just can't use the heavier bullets unless I completely re-zero.

 

[Poper]

Your Vortex scope has target turrets and will return to zero repeatedly. I have the same scope on my silhouette rifle and it works fine.

Using a baseline zero and recording the turret settings for the other various loads would be a simple way to solve the issue of multiple loads.

 

[1911 guy]

What they said.

Dial in for the load you use the most at the longest range you wish to zero for.

Set turrets to zero (scope should have the ability to move the scale to zero without changing reticle position).

Fire groups of the second load at the longest distance you wish to zero for.

Adjust windage and elevation, note and record change from zero you set previously.

Repeat for subsequent loads.

For example, if I zero for M193 at 300, I'll set my turrets to "0" for this load. When i change loads to a Hornady V-Max, I know to turn X clicks up and X clicks left from zero. If I then go to a Berger VLD, I can move X clicks down and X clicks right from my baseline zero. When I go back to M193, I simply return to the baseline zero.

 

[Poper]

Yes, your scope turrets do zero without affecting the reticule position. Just lift up on the turret and move it to the zero mark. Now it is ready for the next load to be zeroed. Returning to the zero settings brings you back to your baseline load.

Great choice for scope, IMHO.

 

[Woolecox]

If you are using your scope as intended, i.e. ranging a target and then dialing in your MOA/MIL’s etc. for the shot, then;

Zero for your most commonly used load, say at 200 yards or whatever range you prefer.

Then shoot your other loads at the same range. Record the offset from zero and enter it into your ballistics program. That is what the offset field is for.

I use the “Shooter" program. Works great.

 

[ajandrs]

Thanks for all the comments guys, I appreciate it! It seems like I was on the right track to zero in the most commonly fired load, then record the click values (offset) for my other load(s). I think I was just over thinking it. I built this rifle as a varmint getter and had zero'd my scope for Hornady's 55gr VMax cartridge. I did adjust the turret using the provided shims to set the elevation zero stop for that cartridge. Then I found out a friends mom had open land behind her property and I started shooting a lot more long range beginning this past winter out to 650-700 yards and the 55gr vmax just doesn't have much going for it at that range so I started loading up some 77gr nosler custom comps for the job. That's mostly what I'll do all summer so I'll reset my zero stop for that load so I can always easily dial back down to zero for that 77gr load. Then I'll shoot my vmax load and record the clicks for that 2nd zero!

Woolecox, great tip on setting the offset in the ballistics calculator. I guess I had just looked over those fields or never learned what they were for (still new to this long range stuff) but I see them now and will use them for all my loads. Knowing that makes it all seem a lot more simple. Thanks again for sharing that!!

Heading out to the range tomorrow to do some more load testing so I'll get my 77gr zero all setup tomorrow and go from there. Should be a mud bath out there considering how much rain we've gotten today!

Thanks again guys!!


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