Shifting Zero on Long Range Hunting Build

hereinaz

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Seriously? No one has even suggested ghosts? My money is on ghosts... tricky little shits.

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Ghosts are right up there next to mirage. You can't always see them, but you know they are there!
 

Hill Difficulty

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herinaz

Respectfully, I'm going to list a few things and leave it at that.

1. My question was intended to address and help the OP.
2. The OP described that he's shooting a 4" diameter target at 400 yards, misses, and represents that all the misses are 4" low. He's not hitting the little gong so somehow able to see where multiple invisible bullets are impacting 4" low at 400 yards distance?
3. Where I'm going with alignment: The OP has a 20 MOA rail + a 50mm bell + ring base height = he's probably 2" scope over bore and has a Ridgeline stock (low comb) with a little glue-on comb riser. Odds are he needs to lift his head too high to anchor a cheek weld.
4. Then this:
How exactly does sight alignment on a scoped rifle make the differences at the yardage here? Do you have any resources I can read up on that?
The OP is low 4" at 400 yards and you're puzzled whether an inconsistent anchor/alignment might cause 1 MOA's worth of difference. :rolleyes:
 

hereinaz

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Respectfully, I will disagree and hope our discussion is helpful to the OP to understand both our positions. OP can go test your cheek weld hypothesis, and next time I go out, I will test it myself. I have never experienced it before, which is why I asked for more information.

1) OP has a 5/8 riser on his cheek so it isn't as low as you might think. I have solved most cheek weld issues with less than two pieces of camping matt and athletic tape. I have also gotten rid of my "cheek weld" and gone to a gentle "jaw index" because a "cheek weld" was too much pressure and induced shooting inconsistencies. In the end, any cheek or jaw weld is an index to make sure we assume the same position.

2) OP said he was accurately hitting steel. Suddenly, he started missing but then after adjusting his zero, he started repeatedly hitting steel for another two hours. It doesn't sound like he is having issues with changing positions. He used the term "about 4 inches low". I can't say for sure, but at 400 yards, if I were spotting and had good trace, I could probably make a guestimate within inches. We often say, "one target low" or "one target high". He said:

I shot at the same target and was hitting about 4 inches low. I then shot at a 200 yard steel target and was hitting around 3 inches low as well. I re-zero'd my rifle and dialed to 3.75 again and began hitting steel at 411 yards again and had no issues for the rest of the day (about 2 hours).​

3) OP had a second shooter verify that the zero was low.

4) The only "mechanical" issue I am aware of from changing head position that would move a group is parallax induced error if he does not center his eye in the scope. And, at the distances he is shooting, he would have to go from one extreme scope shadow looking like a moon sliver to the exact opposite direction with a moon sliver.

We all know that a consistent cheek weld is important for good shooting, but I have never seen that changing cheek weld move a zero that dramatically. Typically an inconsistent cheek weld just makes the groups bigger over all.

Edit to add, you have to make the assumption that he made one dramatic change to his head position and wasn't bouncing between them during the day. To the OP, I would be curious if he did make any other changes between the apparent zero shift.
 
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4ester

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If parallax is set perfect on the scope...... it matters very little on comb height/head position. Which I never saw where he said otherwise......a lot of shooters that are newer often don’t understand how to set it.

4” at 400 yards isn’t very much. Heck his dope chart could be a little off, and was barely tagging the plate to begin with.


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hereinaz

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Agree, perfect parallax makes no difference in sight alignment. I will add that a typical parallax error is so small it isn't going to make a miss at long range.

Parallax seems to be widely misunderstood. I know most of what I read is that parallax error would make you miss. That's simply not true.

If parallax is perfect at 200 yards, and I was shooting at 400 yards

And

If I was looking through the scope with maximum induced parallax so that I could only see a tiny sliver of the scope because it was almost all shadow

The maximum error I could induce is half the width of the objective diameter. On a 50 mm scope that is at most 25mm or one inch. 600 yards the maximum error is 2 inches.

But, that requires the absolute worst aight picture possible. No single competent shooter I have ever heard of would settle for a sight picture where all you can see is a tiny sliver of light. At most, with a slight shadow, you are inducing parallax error of a fractions of an inch at long range.

So, if you shoot long range, and set parallax at 300 yards, the maximum error you could induce at 600 yards is one inch. The maximum at 900 yards is two inches. But remember, this amount of error is only possible when you can barely see through the scope. Center your eye and you practically eliminate parallax error.

If you are getting mostly centered in the scope, you have reduced parallax error to basically nothing. Parallax is only present if you get put of the center of your scope.

If you miss at long range, it isn't because of parallax. But it is easy enough to dial it out when you focus the image. I focus the image and center my eye. I never have a parallax issue, ever.
 

madcalfe

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herinaz

Respectfully, I'm going to list a few things and leave it at that.

1. My question was intended to address and help the OP.
2. The OP described that he's shooting a 4" diameter target at 400 yards, misses, and represents that all the misses are 4" low. He's not hitting the little gong so somehow able to see where multiple invisible bullets are impacting 4" low at 400 yards distance?
3. Where I'm going with alignment: The OP has a 20 MOA rail + a 50mm bell + ring base height = he's probably 2" scope over bore and has a Ridgeline stock (low comb) with a little glue-on comb riser. Odds are he needs to lift his head too high to anchor a cheek weld.
4. Then this:

The OP is low 4" at 400 yards and you're puzzled whether an inconsistent anchor/alignment might cause 1 MOA's worth of difference. :rolleyes:
im not really following where your going with cheek weld either, he was still 4” low at 200yards. And it’s not to hard to see where bullets are impacting providing on the background is this 400 yard target stuck in dirt.... can see a bullet hit dirt at 400 yards pretty easy. Just for reference here’s a ridgeline, 20moa rail, 50mm scope and a piece of foam for a riser pad and was able to shoot out to 1150yards prior to even having the foam in it 254EA041-A66E-43BA-99D3-4919EED4D505.jpeg
 

WRO

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It should be consistent, one thing I can assure you is Vortex consistently fail and won't hold 0.

Don't worry the repaired one will eventually lose 0 as well..
 
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hereinaz

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It should be consistent, one thing I can assure you in Vortex consistently fail and don't hold 0.

Don't worry the repaired one will eventually lose 0 as well..



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I will agree in part and disagree in part. I don't like generalizations.

It is a sliding scale. All scope companies with low end models have high failure rates for us LR hunters at the bottom tier. Rates are still unacceptable to some at the higher mid tier. As you increase cost and quality the rate of failure increases. Vortex highest lines don't fail any more than others.

NF won't make cheap scopes, so they don't have failures. Its why I recommend the SHV as the best budget scope.

I would never buy some Vortex because of high failure rate, but it isn't 100% on their PST II, nothing close to that. Among other things, the variables in a scope are likelihood of failure. You have to talk models.
 

flesher_2006

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So I'm new to long range hunting and this year I have dedicated a rifle build to do just that. I have a Christensen Arms Ridgeline chambered in 7mm Rem Mag. I have Vortex precision match rings mounted to a Talley 20 MOA 1 piece rail. I mounted a Vortex Viper PST Gen II 5-25 x 50 MOA rifle scope. Everything was torqued to spec and the rail was bedded to the action. I have a 5/8' sorbathane cheek riser from Gotta grip on the stock. Im shooting 162 gr Hornady Superformence (SST).

Yesterday I zero'd at 200 yards and got a sub MOA group. I dialed my optic to 3.75 MOA and was hitting a 4 inch steel target at 411 yards,. I was pretty pumped as it validated that I built a good shooting rifle. Well about 15 minutes later I shot at the same target and was hitting about 4 inches low. I then shot at a 200 yard steel target and was hitting around 3 inches low as well. I re-zero'd my rifle and dialed to 3.75 again and began hitting steel at 411 yards again and had no issues for the rest of the day (about 2 hours).

What do you think could cause this? Is there something that I should change or do you think it was from my inconsistencies as a shooter?
Any advice would help.

Thanks
Just to add one more thing to this. There are so many possibilities that it’s hard to narrow down exactly what was going on but I‘m willing to be it’s shooter related. If you were hitting that target consistently at 411 yards then stopped for a break, got back on the rifle and was impacting in a different spot, it was likely due to you breaking your shooting position and then getting back on the gun with a different cheek weld, eye relief, etc. If it was a mechanical issue, it would to have happened the last time you pulled the trigger for that first session which leads me to believe it’s shooter related.
 

hereinaz

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Just to add one more thing to this. There are so many possibilities that it’s hard to narrow down exactly what was going on but I‘m willing to be it’s shooter related. If you were hitting that target consistently at 411 yards then stopped for a break, got back on the rifle and was impacting in a different spot, it was likely due to you breaking your shooting position and then getting back on the gun with a different cheek weld, eye relief, etc. If it was a mechanical issue, it would to have happened the last time you pulled the trigger for that first session which leads me to believe it’s shooter related.
Any ideas what he could have done to enduce such a zero shift?

I have played with different positions trying to shift zero just with position. I can't get one unless I change the suppot. Like from bipod to bag, but it hasn't been that big for me.

I am curious about what mechanisms would move a zero.
 

SecretSpot

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Whether you think people hate on vortex too much or not the fact is it's still junk and you will need their warranty if you buy one. If that hurts your feelings you need to get your life on track cuz your scope probably doesnt
 

WRO

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I will agree in part and disagree in part. I don't like generalizations.

It is a sliding scale. All scope companies with low end models have high failure rates for us LR hunters at the bottom tier. Rates are still unacceptable to some at the higher mid tier. As you increase cost and quality the rate of failure increases. Vortex highest lines don't fail any more than others.

NF won't make cheap scopes, so they don't have failures. Its why I recommend the SHV as the best budget scope.

I would never buy some Vortex because of high failure rate, but it isn't 100% on their PST II, nothing close to that. Among other things, the variables in a scope are likelihood of failure. You have to talk models.


If I was going to by a cheap scope to dial, it would be an SWFA, Nikon fx1000, Bushnell LRHSI/DMR if I was going to buy a good scope to dial it would be a NF/Kahles/ Swaro x5, Tangent, etc. At no point would I risk a hunt on a vortex or leupold I intended to dial..
 
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WRO

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A Nikon... but you won't buy any Vortex. OK.
Yep, FX1000 is a solid scope that can be easily purchased for less than 500.00. I've got 1000 rounds through mine repeatedly dialing with 0 issues. That being said, it's on a varmint rifle.

If I wanted to pay 40% more for a shit in a shoe box warranty I'd gladly purchase a vortex.

I've broke high end scopes, but not nearly at the failure rate I see Vortex's and Leopold's fail at when it comes to repeated dialing. About every other year we have a client with one that's failed their hunt..
 

07yzryder

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I can tell you my brother and i were doing some load verification on his 30 weatherby mag. 4 shots is all it will allow. 4 shots in 3.5-4 inches at 400 yards 5th shot 6 inches low right WTF send one more, about touching the 5th.

wait until barrel is cool 2 shots in with group 1-4 then shots 4 and 5 in with group 5-6. only difference is temp. its repeatable and because its a hunting rifle and not a target gun we accepted 3 shots groups and wait until cool to the touch.

rifle is a 300 weatherby mag meat eater edition, zeiss conquest v4 3.5-14 (or close to that) in zeiss rings on some high end rail.

as far as shooter, i took my 338LM and put 6 rounds in a 2 inch group at 400 so shooter is familiar with recoil and is able to maintain decent accuracy.
 

flesher_2006

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Any ideas what he could have done to enduce such a zero shift?

I have played with different positions trying to shift zero just with position. I can't get one unless I change the suppot. Like from bipod to bag, but it hasn't been that big for me.

I am curious about what mechanisms would move a zero.

In the realm of shooter error, Inducing “cant” in the rifle could more than explain a 4” error at 400 yards. Maybe I missed it but I didn’t read anything about the shooter having a level on his optic.


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madcalfe

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In the realm of shooter error, Inducing “cant” in the rifle could more than explain a 4” error at 400 yards. Maybe I missed it but I didn’t read anything about the shooter having a level on his optic.


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rifle cant would be a left to right and low depending on which side its canted.... not just bang on but 4" low and there would be even less of a drop at 200 yards from a canted sight.
 

LaHunter

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A scope that will not hold zero or not track true or consistent is a really frustrating problem. I have been there and done that. I chased my tail for too long thinking it was me or other things. Unless the scope just totally 'craps the bed', this can be a tough issue to pinpoint because many times the scope problem is not a consistent problem, which leads to tail chasing. I put a NF SHV on my rifle and that was the cure. The OPs problem could be lots of things, but his scope model has its fair share of 'documented' issues on the interwebs.
 

wind gypsy

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I always figured Fx1000 and PST g2 were potato/potahto. Both made in phillipines and seen plenty of people claim issues with both.
 

WRO

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I always figured Fx1000 and PST g2 were potato/potahto. Both made in phillipines and seen plenty of people claim issues with both.
Mine's been very reliable so far. Couple of my buddies have had nothing but success with them. Nikon runs a pretty high QC on even their OEM stuff..
 
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