Rifle Scopes Zero shift w/Leupold Mk4

JaredCO

Steel punisher
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Minuteman
Aug 2, 2011
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Went to the range today to shoot my 260. started at 500 and came up short and right of a 12x12 diamond,wtf. So I shot at paper at 300 and I,m 1 moa low and 1/2 moa right. This gun shoots well under 1 moa and the 300 to 500 dope is the same. Mounts are tight and it hasn't been dropped or roughed up. Do I send it in to get checked out or what? I know my throat is going away but I've got 1100 rounds and not had the zero change. Mark4 6.5-20x50 md by the way
 
Re: Zero shift w/Leupold Mk4

Check your fasteners, re-zero and roll. If the zero changes on your next range trip, then you may have a problem.

I wouldn't worry about it is this is a non-critical apication and it changed once.

If you are worried, run a tracking test and a return to zero check.
 
Re: Zero shift w/Leupold Mk4

It's gotten quite a bit cooler here in CO, I just looked outside now and the DA locally is only about 6500, a normal range day just two weeks ago keep the DA over 8000 ft, in some cases closer to 9000ft so seeing a minute at distance is not beyond unreasonable.

When was the last time you shot at distance with that dope and did you account for the cooler temps ? Baro was down a bit too, about 24.44, so I could see that making a difference.
 
Re: Zero shift w/Leupold Mk4

It's been 2 weeks since I last shot but the dope from 3-500 remains the same, 5 moa. I do need to learn more exterior ballistics. Any reading suggestions?
 
Re: Zero shift w/Leupold Mk4

I'm shooting Berger 140's at just over 2900 fps. I joined Ben Lemond and shoot there mostly. How far can you shoot at Frontier?
 
Re: Zero shift w/Leupold Mk4

The same dope at 300 yards and 500 yards... I think you have an issue, that is not possible even running a 140gr VLD at 2900.

JBM shows

a 140gr VLD going 2900 needs 3.4 MOA at 300 and 8.3 MOA at 500... so you have another issue if you feel the dope is the same.

It just doesn't pass the common sense test.
 
Re: Zero shift w/Leupold Mk4

I'm not explaining well enough. Rifle zeroed at 300yds. Dial up 5 moa to get to 500 yds. Yesterday I dialed up 5 moa for 500yds and came up 1 moa short. Shoot at 300 and still 1 moa low. I reset zero and still up 5 moa to get to 500. For the atmospheric conditions to effect my zero I would think it would also effect the dope. I do not understand all of it, that's why I posted.
 
Re: Zero shift w/Leupold Mk4

It could be the issue maybe, you're zeroed at 300 so you are managing the issue there. You're round is not going to be exempt of changes in atmospheric conditions.

1. I wouldn't' zero at 300

2. You're system may not be as bulletproof you hoped

3. You may have compromised your position with more clothes, that may effect your cheek weld moving your eye into a slightly different position

4. You may not have properly adjusted your parallax

The list is pretty long with the limited information you provided. I ran the data with the current conditions in CO and I see a 5 MOA difference between 300 and 500, 2 weeks ago it may have been 4 MOA or 4.5 MOA in which case .5 MOA for the weather and .5 MOA for you or the rifle.

Not uncommon.
 
Re: Zero shift w/Leupold Mk4

PS, there is a .25 MOA difference at 300 yards changing the temp just 25 degrees, which is pretty close to 2 weeks ago versus this week. (At 300_) At 500 yards there is almost a 1/2 minute difference between then and now... so there you have some difference you are not accounting for.

How that is managed by you along with any change in your position can easily produce a 1 MOA in total error. The system is no just the rifle it is you and the rifle and all those little errors add up --- consistency is key.
 
Re: Zero shift w/Leupold Mk4

At the Fountain range they are working on a 1,000 yd setup. Just take Lowlight's advice and learn a bit more about ballistics. With a 100 yd zero you should be able to reach out quite a ways dialing. Also if you don't have a kestrel get one and learn how to use it. I still can't come close to cleaning the dot drill that's somewhere on here. Good luck though
 
Re: Zero shift w/Leupold Mk4

Just noticed my famed avatar was replaced that's gonna break alot hearts
wink.gif