Shifting Zero on Long Range Hunting Build

[WeiserBucks]

Keep shooting and report back if the results are repeatable. If it's a mechanical issue with the rifle/rings/scope its not going to go away. If you had a proven rifle and scope to shoot along side the new one that would really help narrow it down.

 

[madcalfe]

I'm not by any means saying every Christensen is good, in fact I ran it for 2 years and just sold it to fund a full custom build. I'm just giving the OP my opinion on the facts hes stated. which makes me think that its the scope. if it was me id recheck all the screws to make sure there torqued properly and feed the rifle 1 more box of shells. if its randomly goes out of zero again send the scope off for warranty. no point in wasting 100's of dollars in ammunition, other way of checking your issue would be to put a different scope on it and try it out again. if the constantly groups tight with a different scope then well you know it was a issue with the vortex.

And @406Smith and no offence vortex has the worse reputation for sending out unreliable scopes. I've used their warranty, know others that have had to use their warranty and well its just a common thing that soon or a later your going to be needing their " best in the business, no questions asked VIP warranty"

 

[madcalfe]

We’re getting off topic, but Vortex sells sub $100 scopes and $2,000+ scopes. Talking about them as a brand as a whole is dumb. The Gen 2 PSTs have a pretty good reputation. Vortex sells a ton of them so you obviously will here more problems (basic statistics). Again, it could be a scope issue, but there isn’t enough info.

If you use equipment enough, you’ll use a warranty. Vortex is one of the best. I’ve sent out more than one $2,000+ optics for repair work. Doesn’t mean that brand or product line sucks, it’s just life. Waiting weeks or months & paying to ship to Europe is lame - getting the problem resolved inside a week & not being out any money is nice. How a company treats you is far more important than whether or not you have a problem.

Also, barrels speeding up is a real thing. Sounds like the OP has less than 100-rounds through to rifle. That could account for a little shift. Inconsistent fundamentals shooting a lightweight magnum will definitely play a role.

true barrels do speed up once broken in. but also more speed the higher the bullet placement would be..... so talking about barrel speeding up and having a 4" drop doesn't make sense and also a barrel wouldn't speed up like 150fps randomly after a shot so that theory is out. and that's unfortunate you've have to send back more than one 2000$ vortex scope... I've seen a reticle knocked out of place on their new razor LHT. and yes its true a lot of people buy vortex and probably don't have issues but im willing to guess those are the people that set the turrets and never touch them again. No offence to anyone that uses vortex but their a entry level budget friendly scope. They will have issues.

 

[madcalfe]

The point about barrel speeding up was to further punctuate how little data the OP currently has. He has very few rounds on the new gun with a new scope as a new shooter. His data set is itty bitty. Guys are jumping to the conclusion that it’s gear.

Oh, and I didn’t have multiple vortex scopes fail.

"If you use equipment enough, you’ll use a warranty. Vortex is one of the best. I’ve sent out more than one $2,000+ optics for repair work. Doesn’t mean that brand or product line sucks, it’s just life."
oooook.

OP hope ya figure out what's going on with your rifle I've said my thoughts.
good luck!

 

[Hill Difficulty]

Wen I dialed out to 411 yards after my 200 yard zero I was hitting a 4 inch steel target consistently. I put around 6-8 round on the 4 inch target without a miss. I took a break and the next time I shot at the 411 yard target I was missing and was impacting +/- 4 inches low.

How do you know you're impacting 4 inches low on a 1 MOA steel target at 400 yards?

Other is sight alignment anchor escapes a lot of experienced shooters. Going back to your original question, I'd encourage you to examine your eye alignment in relation to stock comb height, particularly when shooting such high magnification and having to clear a big 50mm bell.

 

[hereinaz]

A second shooter apparently verified it was low. Assuming it isn't the shooter, and taking his statements true about groups, it is mechanical.

The shift won't be because of sight alignment. Parallax error can't physically be that far. And, he would have to have massive scope shadow that would be obvious to any decent shooter.

It could be ammo, but only if it were a different lot.

It is most likely mechanical. Something slipped in the rings/base or the scope broke. It could have been something moved with the rifle, but that is unusual.

Double check the mounting, and if it isn't that then it is likely the scope that is broken.

I would take it out and zero it at 100, work the dial over and shoot a tall target test at 100. Try to replicate the error.

 

[hereinaz]

The point about barrel speeding up was to further punctuate how little data the OP currently has. He has very few rounds on the new gun with a new scope as a new shooter. His data set is itty bitty. Guys are jumping to the conclusion that it’s gear.

Oh, and I didn’t have multiple vortex scopes fail.

Agreed, he doesn't have enough data. One outing and one trip aren't enough to tell what is up. That's why I suggested to tear down the scope mounting and redo it with loctite or resin inside the rings. More often than not, I'd say odds are good that problems like a zero shift on a new rifle are because of something knuckleheaded we do.

Redo the scope mounting and go get more data at 100. Get a big sheet of paper with a grid on it and crank the scope around. If the scope is broken, it should show up. Shooting those bullets, you will be breaking in the barrel, getting data and if there are gremlins, you'll discover them more easily on paper at 100 than any other way. You can also work on your form, so it isn't all just a waste of time.

 

[Hill Difficulty]

A second shooter apparently verified it was low.

Huh?

Assuming it isn't the shooter, and taking his statements true about groups, it is mechanical.

Or, assuming it isn't mechanical, it's the shooter.

The shift won't be because of sight alignment. Parallax error can't physically be that far. And, he would have to have massive scope shadow that would be obvious to any decent shooter.

Misalignment has nothing to do with parallax.

 

[hereinaz]

Hill, read the OP post and comments. A second shooter verified it is low. If his groups are as small as he says, then shooter error is less likely. That is why i said what I did. If he is lying or exaggerating, well I am not here to call him out.

Please explain exactly what you mean by

"sight alignment anchor escapes a lot of experienced shooters. Going back to your original question, I'd encourage you to examine your eye alignment in relation to stock comb height,"

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?

 

[4ester]

Go do a tall target test and check tracking.

In my mind it sounds like mounting issue, parallax, shooter issues, ammo..... or a combination of all. Is the rifle barrel floated correctly? Action bedded and torqued?


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[wind gypsy]

I don't have a clue what the problem was but as long as we're throwing out ideas:

1. Scope mechanical issue
2. Scope mounting issue - Including scope base screws making contact with the barrel tennon.
3. Something related to action screws, rifle shifting in how it is bedded to the stock, or stock contact point on barrel.

 

[bsnedeker]

I don't have a clue what the problem was but as long as we're throwing out ideas:

1. Scope mechanical issue
2. Scope mounting issue - Including scope base rings making contact with the barrel tennon.
3. Something related to action screws, rifle shifting in how it is bedded to the stock, or stock contact point on barrel.

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

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[hereinaz]

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]

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.

 

[hereinaz]

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.

 

[4ester]

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]

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]

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.

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

 

[WRO]

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..

 

[hereinaz]

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.