Rezero with new ammo?

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I’m shooting a Tikka 7mm RM, and if I could go back in time, I’d buy a couple of cases of Federal 160 grain accubonds for it and use them for everything. But with ammo the way it’s been the last couple of years I’ve picked up random boxes of this and that as I’ve found it. I have everything from 130 grain copper to 175 grain powerpoints and everything in between.
How do you handle re-zeroing and figuring new drops when switching ammo? I’d hate to use half a box every time.
 

davsco

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yep the ol' fashioned way. by actually shooting to see where you're hitting and adjust your scope accordingly. good news is you should be relatively close.

figuring new drops, just use a ballistics program which should get you pretty close, never hurts to shoot to confirm esp as you get past a few hundred yards if you will be shooting that far.
 
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zion zig zag
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yep the ol' fashioned way. by actually shooting to see where you're hitting and adjust your scope accordingly. good news is you should be relatively close.

figuring new drops, just use a ballistics program which should get you pretty close, never hurts to shoot to confirm esp as you get past a few hundred yards if you will be shooting that far.
This is what I was wondering. Zero at 200. Use ballistics program to figure drops out to 500 and then confirm with a few shots. Should leave half a box for hunting. I’m guessing if I knew someone with a chronograph I’d be even closer with fewer shots?

And I’m not exactly a long range hunter. I’ve shot one animal at slightly over 400, I’d say average is closer to 200. Just curious how other people handle this situation.
 

Laramie

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I use two 3 round groups as long as they are grouping consistently. I never understood the 10 round groups. Shoot 3, measure & perform exact adjustment needed, then shoot 3 round group to verify. Repeat if necessary but that is rare if you do it correctly.
 

WCB

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If you have a box or so of random stuff there is zero use IMO of trying to build a chart for :long range"...now 400 yards or so fine use the numbers on the box and you'll be fine.

As far as sighting in...break off your first shot clean. lock your rifle down on the bullseye and dial your scope to meet your bullet hole. Next shot should be right on...shoot another to confirm. You now have a basic zero. If you really want to dial it in from there shoot more. I have no idea how it takes guys 1/2 a box to get a basic 100 or 200 yard zero.
 

ID_Matt

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If the gun is accurate and scope tracks consistent then you should be able to get zero'd with way less than 10 rounds. If you did it perfectly, I would say 2-3 shots to get zero, 3 shots on a different POI to verify accuracy. As far as verifying ballistic info, if you are trying to save ammo you could shoot all of this through a chrono that isn't touching the barrel.
 

OXN939

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Just curious how other people handle this situation.

You can get a decent zero with six rounds- one three round group (assuming the first group is on paper) then adjust and shoot a second 3 shot group to confirm. If there were only 20 rounds of whichever load I was shooting in the universe, I'd use 4 more rounds practicing out to 200 and set that as my MER.

To consistently shoot with ethical accuracy past 200, you'll need more than one box of ammo.
 
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zion zig zag
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If you have a box or so of random stuff there is zero use IMO of trying to build a chart for :long range"...now 400 yards or so fine use the numbers on the box and you'll be fine.

As far as sighting in...break off your first shot clean. lock your rifle down on the bullseye and dial your scope to meet your bullet hole. Next shot should be right on...shoot another to confirm. You now have a basic zero. If you really want to dial it in from there shoot more. I have no idea how it takes guys 1/2 a box to get a basic 100 or 200 yard zero.
Ha, I guess 400 yards is long range in my world.
 

thinhorn_AK

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I’d just get it on target then fire a 3 shot group or 2 to make sure it’s doing what you want. That’s all I’ve ever done. I’d never feel obligated to shoot a 10 shot group unless I just felt like it.
 

davsco

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This is what I was wondering. Zero at 200. Use ballistics program to figure drops out to 500 and then confirm with a few shots. Should leave half a box for hunting. I’m guessing if I knew someone with a chronograph I’d be even closer with fewer shots?
chronographing is best, then drop actual speeds and gun/bullet info into a ballistics program and then actually shoot and that should be real close. or you could use the drops on the ammo box and actually shoot and see where you're hitting and adjust your drops accordingly.
 

PNWGATOR

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You’re pissing in the wind shooting three round groups and adjusting zero. Three round groups are statistically irrelevant if you want to ‘zero’ your rifle.
 

JakeSCH

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You’re pissing in the wind shooting three round groups and adjusting zero. Three round groups are statistically irrelevant if you want to ‘zero’ your rifle.

I think it depends on how far he plans on shooting his rifle. If he is only shooting 200 or 300 yards, a couple shots will get you close enough. Then use a couple more to verify drops.

However if he is planning on shooting past 400y or 500y (by his post I seriously doubt it) then I agree more work is required.
 
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If the gun is accurate and scope tracks consistent then you should be able to get zero'd with way less than 10 rounds. If you did it perfectly, I would say 2-3 shots to get zero, 3 shots on a different POI to verify accuracy. As far as verifying ballistic info, if you are trying to save ammo you could shoot all of this through a chrono that isn't touching the barrel.
I couldn’t do it in 2/3 shots…
 

ID_Matt

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I couldn’t do it in 2/3 shots…
2-3 shots would be pretty ideal. If you have a good tracking scope and hit paper the first shot.... measure the distance you are off from zero either with the reticle or by hand, make a full adjustment. Shoot 1 more, if it is off by a bit, adjust again. If it is close, shoot 2 more in to a group then make a final adjustment if needed.
 
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