• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Do you need to rezero after calibrating MV?

Dunraven

Major Hide Member
Full Member
Minuteman
Feb 1, 2019
1,681
2,002
Today I checked 100 yard zero on my 6XC and 6.5x47. Then shot them both at 450 to check Kestrel settings. Then shot them both at 984 yards, using Kestrel 5700 elite settings. Both rifles happened to be about a foot high at 984, so I calibrated MV in Kestrel to adjust POI back down. Is it necessary to recheck zero again? I wouldn't think it would change, but maybe so? Went through all this because the XC was shooting high in a match, even tho it seemed right on at 450 before leaving home. Thx.
 
You have a lot more going on than a zero issue. If your zero is good and your kestrel data is good at 450 you probably need to true your bc at your longer range. You should spend a couple hours researching and also try to find a chronograph. And your "about" a foot high is not something to go off of. I'd be shooting fresh painted steel or paper that way you take the "about" completely out of the equation. And after you zero a rifle it's zeroed, no need to change it unless you change ammo or weather or ......
 
I don't have a chronograph so I get a solid zero @ 100 then gather my real world drops at 4-5 different distances out to a grand or so, then I play with my settings until everything lines up.
 
  • Like
Reactions: Seymour Fish
No need to re-zero.

I’d be looking at time of day for light angle and also mirage. When you zero’d vs when you were truing. And when you were truing to when you were shooting match.

Pretty easy to be .3 (almost a foot) high at distance due to lighting and/or mirage.
 
You have a lot more going on than a zero issue. If your zero is good and your kestrel data is good at 450 you probably need to true your bc at your longer range. You should spend a couple hours researching and also try to find a chronograph. And your "about" a foot high is not something to go off of. I'd be shooting fresh painted steel or paper that way you take the "about" completely out of the equation. And after you zero a rifle it's zeroed, no need to change it unless you change ammo or weather or ......
I am shooting freshly painted steel all the time. I know exactly how many mils high it was for both rifles, just didn't think it mattered for my question. Also do have a chronograph. Magnetospeed.
 
No need to re-zero.

I’d be looking at time of day for light angle and also mirage. When you zero’d vs when you were truing. And when you were truing to when you were shooting match.

Pretty easy to be .3 (almost a foot) high at distance due to lighting and/or mirage.
It's overcast today. No mirage that I saw. 50 degrees. The 6.5 WAS .3 high; the XC was .4 high.
 
If it’s high at distance, and you’ve ruled out light refraction and mirage, it’s a BC issue or a scope turret issue (not perfectly .1 increments that stack up eventually).
 
If it’s high at distance, and you’ve ruled out light refraction and mirage, it’s a BC issue or a scope turret issue (not perfectly .1 increments that stack up eventually).
My understanding of the kestrel is that when 'calibrating mv', it's mv that's adjusted. Is that not correct? I admit that process is not perfectly clear to me, even when following directions! My POI seemed to be changing between home and a match. Once, the last thing I did before leaving home, was to check POI at 450. The first stage was at 448. I'm thinking I got this, but shot right over a 10 inch plate from a modified prone. Tried to check the scope tracking today too, by shooting zero settings at 100, then dialing up 10 mils. The distance between the 2 groups was 37 inches instead of the expected 36. Don't know if this is enough to worry about.
 
Last edited:
Your posts are confusing.

If you’re consistently high at all ranges = zero is off or MV is wrong in calculator

If you’re hitting where you intend at say 400, but it’s off at 900 = BC is wrong or scope tracking issue.

This is of course assuming the shooter isn’t to blame.

Also, scope tracking tests should be done without shooting as that has a much higher chance of shooter induced errors. Something heavy needs to hold the optic down while you dial it up and down a plumb line with measurements.
 
Could be number of factors going on here. If it is high, the MV or BC that how you choose to calibrate, would have to be changed quite a bit. That alone tells me there is something not set right. Calibration is a fine adjustment when everything is set up and repeated correctly.

So, trying to help identify where the cause might be like dthomas and paydirt are trying to get at. We need a little more information on zero and calibration you accomplished. Such as, was it all done prone or combination of bench, do you dial or hold elevation, mechanical tracking done, BC for bullet correct, kestrel inputs correct for calibration, mv temp table considered for the type of powder used, any elevation changes.

Let us know, trying to help.
 
I've been 'chasing' these kestrel settings for 2 years now. Got it to help with wind calls, but honestly never had these kinds of issues when just using the Shooter app; made a 1200 yard coldbore shot in a borderwars match that way. Even sent it in to see if there was something wrong with the kestrel itself. I believe I know how to use the 'calibrate mv' function in there. I've had to do it 6 or 8 times! So, maybe not. As far as shooter error, I have benchrest, f-class, prs experience, tho far from a pro skill level, but quite a ways from a newbie. I shoot prone whenever possible, eg zeroing at 100, n the 450 distance. I shoot 984 by going next door to my farmer/neighbor, but shoot off my truck tailgate rather then lay in the mud; may be an issue there. Bullet bc taken from kestrel library. Using the 'custom' program. Yesterday, I adjusted elevation settings based on impacts at 984, n my last shot hit a 1 1/4" dot, so when the settings are correct, the rifle shoots. Thx for the input. Need any other info?
 
Your posts are confusing.

If you’re consistently high at all ranges = zero is off or MV is wrong in calculator

If you’re hitting where you intend at say 400, but it’s off at 900 = BC is wrong or scope tracking issue.

This is of course assuming the shooter isn’t to blame.

Also, scope tracking tests should be done without shooting as that has a much higher chance of shooter induced errors. Something heavy needs to hold the optic down while you dial it up and down a plumb line with measurements.
Have not heard of checking the scope that way. Directions I found said to shoot 2 groups on a vertical line, 1 at zero, the other after dialing 10 mils. Like the idea of not shooting.
 
  • Like
Reactions: Dthomas3523
Have not heard of checking the scope that way. Directions I found said to shoot 2 groups on a vertical line, 1 at zero, the other after dialing 10 mils. Like the idea of not shooting.

If you don’t have one, order a ruler in 1/10 inch marks. Or use cm/mm. I use the 1/10.

I Use a 3ft level and make a vertical plumb line on cardboard target. Mark every 3.6”. Measure off exactly 100yds and place the center of turrets there. Scope needs to be mounted to something heavy or locked in.

You can do the same thing for horizontal windage.

Every mil should line up with your marks.
 
Today I checked 100 yard zero on my 6XC and 6.5x47. Then shot them both at 450 to check Kestrel settings. Then shot them both at 984 yards, using Kestrel 5700 elite settings. Both rifles happened to be about a foot high at 984, so I calibrated MV in Kestrel to adjust POI back down. Is it necessary to recheck zero again? I wouldn't think it would change, but maybe so? Went through all this because the XC was shooting high in a match, even tho it seemed right on at 450 before leaving home. Thx.
Was there a significant gain in altitude or DA ?
 
I've been 'chasing' these kestrel settings for 2 years now. Got it to help with wind calls, but honestly never had these kinds of issues when just using the Shooter app; made a 1200 yard coldbore shot in a borderwars match that way. Even sent it in to see if there was something wrong with the kestrel itself. I believe I know how to use the 'calibrate mv' function in there. I've had to do it 6 or 8 times! So, maybe not. As far as shooter error, I have benchrest, f-class, prs experience, tho far from a pro skill level, but quite a ways from a newbie. I shoot prone whenever possible, eg zeroing at 100, n the 450 distance. I shoot 984 by going next door to my farmer/neighbor, but shoot off my truck tailgate rather then lay in the mud; may be an issue there. Bullet bc taken from kestrel library. Using the 'custom' program. Yesterday, I adjusted elevation settings based on impacts at 984, n my last shot hit a 1 1/4" dot, so when the settings are correct, the rifle shoots. Thx for the input. Need any other info?
Dunraven, another obscure thought : are you holding the rifle the same from home to match ? Tendency is to hold harder in a match sometimes due to excitement, time pressure, etc. you have experience, so unlikely, but worth consideration. Tailgate = any bounce in bipod ? Sounds sketchy unless something under the feet to mimic shooting off dirt. Sure could explain it. Seymour
 
Dunraven, another obscure thought : are you holding the rifle the same from home to match ? Tendency is to hold harder in a match sometimes due to excitement, time pressure, etc. you have experience, so unlikely, but worth consideration. Tailgate = any bounce in bipod ? Sounds sketchy unless something under the feet to mimic shooting off dirt. Sure could explain it. Seymour
It's possible. Have had same thing happen when shooting off a steel bench at a buddy's range. Had a match last Saturday and did not seem to have an issue this time. Again, last thing I did was shoot at 446 using kestrel reading: hit 1 1/4 inch circle, prone, and called it good. Appreciate the input.
 
  • Like
Reactions: Seymour Fish
No it won’t have an effect on your zero after you fix you mv it just could be that there might be an increase in speed in your load so to true your mv would be fine