Rifle Scopes Does long road trip cause a shift in zero ??

Something is loose or got jarred.

Shouldn’t matter and definitely not that much.

Your scope failed to maintain and hold zero. Maybe due to loose rings, a bump or some thing, etc. But it wasn't simply that it lost zero due to traveling.

Get it checked out to be sure nothing is loose.

*creedmoor

Your rings are loose or your reticle canted.

harry_x1 said:

I mounted the scope on my own and it was my first time, so it could very well be canted.

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Did you use a plumb line and flashlight? Easy way to do this.

What is the scope and agree with the others more than likely something is loose

If the cant was the same in both places the zero would be the same in both places. The scope shifted, the action shifted because something was loose or jarred by the trip.

Constant vibration all the way across the country. Double check everything. Loosen then retorque to spec.

Obviously, a 20” Shift is some kind of equipment issue... well-addressed above.

But small poi shifts will also happen simply due to different atmospherics and temps and air densities in of one part of the world vs the next. External ballistics are a mass of variables!

When traveling to a school or comp or even a hunting area, always check zero or re-zero upon arriving and note your new zero in your data book, etc.

Often, you will get ‘home’ and find your zero is right where it was before you left. Put that in your data book, too.

Environmental issues move zeros a lot more than randomly failing scopes. A good scope is not going to move driving on interstate highways for 3k miles. Any more than it would move in a cruiser trunk after 3k miles on country roads or 500 miles of bad road in a Hmmwv. A 20” shift after tame interstate roads (my assumption) is that you will find an obvious smoking gun issue in mounting screws or action torques... or it’s time for your scope to get serviced.

But Miami and Seattle are very different air densities, temperatures... even latitudes if you are shooting super ELR. So a small shift would be completely expected.

This is why your data book and dope are so important. If you don’t write it down... it never happened. When you do have your data... you have references and patterns emerge.

As for dealing with equipment... run your turrets every now and then so the erectors don’t stick. One should also have index marks on screws. And a torque wrench to check all torques on scope and action after a long trip or at set intervals (once a month? Every time you shoot... whatever).

What may sound like OCD behavior is how precision marksmanship is done.

Let us know what it turns out to be and good luck!

Cheers,

Sirhr

harry_x1 said:

Hi team - I recently made a road trip from miami to seattle. All this while my 6.5 creedmore rifle was stored in the bad of my truck in a rifle bag. On reaching seattle and going to range, I realised that the zero has shifted almost 20 inches high. I was super surprised by that. Is this something that someone else has also experieneced ? I have re zeroed the rifle but not sure if the scope is loose or something, hence checking with the group... thanks

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Update please? Was there equipment issues?

Barrel and loose mounts. You are putting far to much emphasis on atmospherics, in my experience.

I recently Did a similar trip from Houston to Vancouver. Several stops, including shooting, along the way. No atmospheric change in zero from sea level in TX to the range in Colorado with a 35 degree drop, 9800 ft gain in density altitude, and a 55% drop in humidity. Similar conditions minus the altitude (back down to 1500 ft density altitude) in Vancouver. Zero shift. Drop at distance is easily calculated and overcome. Very minor variations in flight never accounted for more than .2 mils in error out to 1200 yards.

I may have missed it but what was the scope on the rifle?

harry_x1 said:

Here's a quick update. Have I found a definitive answer to the issue? No. However, I believe I have a good estimate of what went wrong. After gaining more shooting experience in various matches across the country, I've come to realize that atmospheric conditions play a significant role and can lead to notable deviations in zero. For instance, Miami will differ greatly from Seattle due to variations in altitude, temperature, and humidity, all of which can act as significant variables. While these factors could explain 10" shift at most extreme conditions, the remaining 10 inches may have resulted from the rifle traveling a long distance over multiple days with constant vibrations. It's likely that something loosened during transport, causing the scope to deviate further.



It's important to note that this is also related to the barrel being removed from the gun and reattached after arrival. In essence, the issue stemmed from three different factors: 1) weather and location, 2) loose nuts during travel, and 3) removing and reinstalling the barrel.

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Cool. So do you have any info as to if the zero was back to original point when you returned home?

Makinchips208 said:

Cool. So do you have any info as to if the zero was back to original point when you returned home?

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Yeah, like did it now shoot 20” low after returning home with the Seattle zero.

I’m with the crowd that says equipment and not environmental for a 20” shift at 100 yds.

Baron23 said:

Yeah, like did it now shoot 20” low after returning home with the Seattle zero.

I’m with the crowd that says equipment and not environmental for a 20” shift at 100 yds.

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Right. I’m not bagging on the op, I’m thankful he asked the question.
Just curious why. He did mention the barrel removal and reinstall as part of the reason.

Maybe I'm a moron but what kind of DA shift would have to happen for a 20 Inch shift at 100 yards? If the op Said he zeroed on Venus and then traveled to Pluto I could see it.

Baron23 said:

I’m with the crowd that says equipment and not environmental for a 20” shift at 100 yds.

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thats 20 moa, 6 mils...
99.999% chance it's mechanical cause

ma smith said:

thats 20 moa, 6 mils...
99.999% chance it's mechanical cause

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Ah yeah, I think we are in violent agreement.

harry_x1 said:

Here's a quick update. Have I found a definitive answer to the issue? No. However, I believe I have a good estimate of what went wrong. After gaining more shooting experience in various matches across the country, I've come to realize that atmospheric conditions play a significant role and can lead to notable deviations in zero. For instance, Miami will differ greatly from Seattle due to variations in altitude, temperature, and humidity, all of which can act as significant variables. While these factors could explain 10" shift at most extreme conditions, the remaining 10 inches may have resulted from the rifle traveling a long distance over multiple days with constant vibrations. It's likely that something loosened during transport, causing the scope to deviate further.



It's important to note that this is also related to the barrel being removed from the gun and reattached after arrival. In essence, the issue stemmed from three different factors: 1) weather and location, 2) loose nuts during travel, and 3) removing and reinstalling the barrel.

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Environment will definitely not impact your zero significantly.

Consider what would be required to do so......for example, a 6.5cm running 2700 MV will still have around 2575 velocity at 100yds.

There's no amount of environment that will cause something moving that fast to significantly deviate at 100yds. This is one of the reasons we use 100yds zero.


Your Dope will be different due to environment, but not your zero.

For reference, here is the response to a Q&A with Applied Ballistics:

Your zero is your zero for a reason. If it shifts, it's equipment issues. Whether that means scope, scope rings, scope base screws (if applicable), or the barreled action shifting in the stock/chassis I can't say.

Agree that it's not the equipment.

I can take my rifle to multiple different states and environments, and my zero will barely move. I can take my rifle with confidence with a zero in AZ and travel to say CO, and know that my zero is intact.

Now, if you ask me to make a hit on a 1,500 yard target, using environmental data from AZ summer when I'm shooting in CO's winter, that's a completely different story...

kthomas said:

Agree that it's not the equipment.

I can take my rifle to multiple different states and environments, and my zero will barely move. I can take my rifle with confidence with a zero in AZ and travel to say CO, and know that my zero is intact.

Now, if you ask me to make a hit on a 1,500 yard target, using environmental data from AZ summer when I'm shooting in CO's winter, that's a completely different story...

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And @Rio Precision Gunworks
So info like this video below is extremely goofy. And btw, I disagree with 90% of said video.

I agree zero is zero.

Skip to 18:40 ish for where he says “we are always chasing our zero.

harry_x1 said:

loose nuts during travel

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You mean like the loose nut behind the trigger?

harry_x1 said:

View attachment 8384447

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Dat’s nice.

But please answer this question, after rezeroing in Seattle, did it shoot 20” low in Miami?

Baron23 said:

Dat’s nice.

But please answer this question, after rezeroing in Seattle, did it shoot 20” low in Miami?

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I'm curious as well.

Is the OP able to map out their zero shifts between locations/environments predictably?

kthomas said:

I'm curious as well.

Is the OP able to map out their zero shifts between locations/environments predictably?

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Or at least tell us the magical ammo that's gaining or losing thousands of fps of muzzle velocity based on the weather and humidity. Seems like something the manufacturer should be made aware of.

Action screw issue.

harry_x1 said:

View attachment 8384447

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I'm definitely "cocksure" that you're not experiencing a 10" zero shift do to extreme environmental shift. As well as sure you don't understand how much of any of this works.

Makinchips208 said:

And @Rio Precision Gunworks
So info like this video below is extremely goofy. And btw, I disagree with 90% of said video.

I agree zero is zero.

Skip to 18:40 ish for where he says “we are always chasing our zero.

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A lot of it is a bit weird. But I think what they mean about chasing zero is that you're likely not zero'd with just a few shots here and there. Which isn't wrong, just a bad way they explained it (among other things).

When you take 3-5 shots at 100yds with your bolt gun, there is a fair chance you aren't perfectly zero'd. And you can make small changes each range trip until you have a zero that is quite a bit more precise with many more rounds on the "zero."

I personally use a drill that is about 30-40 rnds from different positions to zero a rifle before a match. Almost never just shoot 5 shots or so and call it good.

Makinchips208 said:

And @Rio Precision Gunworks
So info like this video below is extremely goofy. And btw, I disagree with 90% of said video.

I agree zero is zero.

Skip to 18:40 ish for where he says “we are always chasing our zero.

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Why your rifle isn’t zeroed? From the thumbnail, I’d say because you have no front OR rear support, you’re balancing the rifle on the mag, and the buttstock isn’t even in the same zip code as your shoulder pocket. (That’s just from the thumbnail though, I didn’t watch it).

Rio Precision Gunworks said:

I'm definitely "cocksure" that you're not experiencing a 10" zero shift do to extreme environmental shift. As well as sure you don't understand how much of any of this works.

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In case you didn’t know, this OP has an almost uncanny consistent history of asking “innocent” questions about things he doesn’t know, then insulting the hell out of everyone who gives an informed answer that doesn’t conform to the pre- conceived explanation he had in his head before he ever asked the question. Pretty much every thread he’s ever started ends up the same way.

harry_x1 said:

It's important to note that this is also related to the barrel being removed from the gun and reattached after arrival. In essence, the issue stemmed from three different factors: 1) weather and location, 2) loose nuts during travel,

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It had nothing to do with enviros. You may see a very minor shift in zero due to enviros, basically negligible and more likely related to a zero error.
Loose fasteners will definitely cause shift during travel and shooting.
Removing and re installing the barrel also likely had a factor. Last time I swapped barrels and nothing else my zero moved like 3”.

Miami (2m) and seattle (53m) are both at the functional equivalent of "at sea level ..."

We had an inexplicable wandering zero on a friends rifle - we had mounted the scope, rings torqued tight, blue locktite, Nightforce scope and rings, just couldn’t get to the bottom of it. Ultimately right before sending the rifle back to Christensen we found the screws from the action to the rail weren’t lock tited or torqued enough from the factory, and they worked loose over time. It was almost imperceptible but enough to miss big at distance.

I've heard that high heat in a vehicle/trunk could cause some shape changes/deformation in many composites, polymers, fiberglass, and bedding compounds... I ask the following because I don't know the answer: could a very hot trunk/pickup bed have effected any of the above materials in a stock or bedded chassis and caused the OP's symptoms?

Milf Dots said:

I've heard that high heat in a vehicle/trunk could cause some shape changes in many composites, polymers, fiberglass, and bedding compounds... I ask the following because I don't know the answer: could a very hot trunk/pickup bed have effected any of the above materials in a stock or bedded chassis and caused the OP's symptoms?

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Anything is possible when things get hot enough.

Rio Precision Gunworks said:

Anything is possible when things get hot enough.

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Yeah, I mean it can’t be tight if it’s liquid!

harry_x1 said:

…It's important to note that this is also related to the barrel being removed from the gun and reattached after arrival…

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Here’s the elephant in the room. Is this is factory rifle? Have you removed and reinstalled the barrel before with any zero shift? Factories usually torque down the barrels way more than needed so that ordinary owners cannot remove them easily. When you put the barrel back on, recommended torque is much less than from factory and its new position may not match up.

harry_x1 said:

that reminds me of one factor that I might not have considered. It is axmc with a switch barrell...it could very well be that the barrel came loose during all that travel. I do not remember if I torqued the barrel properly again before checking the zero.

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Here‘s a related thread you may find interesting:

I have never seen that much shift even when swapping barrels on a quality rifle.
If the info given was accurate there is something mechanically wrong in a big way.

harry_x1 said:

Agreed. But I guess it is not the swap of the barrell which was a problem.. it is ai axmc and I had taken off and reattached barrell multiple times without loosing zero.. I suspect the barrell could have come loose due to the prolonged travel with constant vibration… I took it out of the case after 4 months and a 3000 mile trip and shot it at a very diff place…not sure, but another reasonable guess

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Harry, FFS….why won’t you answer the simple dang question you were asked multiple time.

After rezeroing in Seattle, did the gun then shoot 20” low when back in Miami. Surely you must know, right?