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Rifle Scopes Seven Scopes with Issues or Something Else

Seems I have a scope issue times seven scopes. It also seems like this is a legit issue. So, with that said I have a question for you dudes. Has anyone else seen an impact shift when dropping the rifle on a bag and taking a shot?

What started all this was trying to get my build and break times down. Iā€™d shoot five shots from five different positions for time trying to keep them all in the #1 diamond on the Kraft Target. When I went from high kneeling to standing I dropped the rifle on the bag from about 12ā€ in a hatchet type movement pushing to make up time. Hand on grip, forearm approximately 12ā€ above the bag and let the rifle drop angling down to the bag. I noticed the shot went low when I called it center diamond. I shot again to confirm and it was center. I thought that was weird so I repeated the process and first shot was low, second shot was center. My mind went into overtime knowing there was an issue, but what was causing it? My first thought was chassis. Swapped around with three chassis to no resolve. Ok, itā€™s a barrel issue, again three barrels with no resolve. So I texted a dude that likes to test stuff. He said nope never tested that or heard of it but Iā€™ll look into it. Only one thing left to do swap scopes and see whatā€™s up. The results are below and they speak for themselves. What say you?

Here is the process I used to confirm the results checking different scopes.

- All shots were from standing position.
- Held grip, the rifle is 12ā€ above bag, release forearm and rifle falls onto bag.
- Fire first shot.
- Pan over to next target and fire second shot.
- Pick up rifle and repeat for a total of 5 shots per target/10 rounds total.

Here is the list of scopes tested:
- Gen 2 Razor 4.5-27
- Zero Compromise 4-20
- Nightforce NXS 5.5-22
- Gen 3 Razor 6-36
- Leupold MK4 Fixed 16x
- Gen 2 Razor 3-18
- Viper PST 5-25

Chassis that were tried early on to eliminate that thought:
- AIATX
- XLR Envy Pro
- Early XLR Envy

Barrels Tested to remove that thought:
- 26ā€ Proof 6mm
- 26ā€ Bartlien
- 26ā€ Proof 6.5mm

The last thing I tried was dropping the rifle onto the bag dialing the scope up and down to remove any lash then return to zero and fire. It fixed nothing.

Will work for ammoā€¦.

@Lowlight feel free to move if this needs to be elsewhere.
Am I reading this correctly, the first shot after the "drop" is low but the second is POA? and this without adjusting the scope?
 
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On mounts: I have seen cooky thing with mounts that could potentially explain this. It comes down to the clamp design and how much friction is built into it. Generally, in a well designed mount, zero retention should not be related to friction between the pieces, but I have seen this be all over the place.
For nothing but zero retention, what's your scope rings or mount of choice? I don't think I need many features, I just want something that my scope will never shift in. Is there a top dog on just sheer clamping force or friction on the scope/rail?
 
Thatā€™s it
Since the zero moves and then comes back to original, it would seem that the most likely source would be the scope adjustment mechanism. Most modern scopes use very similar designs as far a s internal adjustments. Col. Cooper may have been correct that a fixed scope and an adjustable mount could be more robust if only because there is more room outside the scope tube than inside even with 34mm and 35mm tubes. I cannot see how the chassis or mounts could move and then return to the former position.
 
Since the zero moves and then comes back to original, it would seem that the most likely source would be the scope adjustment mechanism. Most modern scopes use very similar designs as far a s internal adjustments. Col. Cooper may have been correct that a fixed scope and an adjustable mount could be more robust if only because there is more room outside the scope tube than inside even with 34mm and 35mm tubes. I cannot see how the chassis or mounts could move and then return to the former position.

An impact/jostle puts a slight bind/tweak on multiple parts with space to shift that is resettled after the firing explosion/recoil

When testing chassis bedding/POI shifts pre-bedding, I could move my POI around in various directions depending on which way i struck the barrels

Some directions would shift and tend to stay until I hit them back the opposite direction, some would shift and walk back to center over a few shots

I was impacting way harder than a small drop from 12ā€ onto a bag so I could see how a consistent/lesser impact could move things just enough for recoil to reseat it each time

After bedding all the shifts went awayā€¦same scopes were used before and after
 
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Simple problem, simple solution.
C'mon guys think.....it's easy.

When you drop the rifle it allows *debris* (carbon, copper chunks, unburnt powder, etc.) currently in the bore from previously fired shots to be dislodged creating a slower shot hence the low hit.
The next shot has the now cleared bore so it will be right back on target.

Might as well just drop a handful of dirt in the bore to test this out.....it'll do the exact same thing.

Nothing is failing and everything is acting normal.
I'm puzzled y'all couldn't see this.

Oh, the fix ?
Don't EVER intentionally drop your rifle dumbass.
Isn't that jarhead 101 ?
It's your lover, treat it as such.

Oh, the test to confirm ?
Chrono the shots after dropping the rifle.
It's a no brainer, right ?
 
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I donā€™t know whether the following is sarcasm or science, but I gotta ask:

Does this happen with iron sights?

Does this happen with a scoped rifle that doesnā€™t have a stock separate from an action ā€” like an AR platform?

-Stan
 
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Barrels are torqued at 85ftlb and action screws at 65inlb.

Iā€™ll try a gasser whenever I get time. You know for science and the internetssss.
 
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That's a pretty easy one to check. Just mount a visible laser on your scope. Look at the dot through your scope and see if it moves.
If it's not the scope, then mount it on your barrel, chassis or whatever and use the process of elimination.

P.S. Use a quality laser so you don't add another variable.

Something like this would be perfect to test exactly the way you suggested.

 
Someone please test this with a bedded chassis. Thereā€™s a reason many of us bed them. Iā€™ve found that most chassis experience small zero shifts throughout a prs match and moving in and out of the truck between days with shit getting piled on and what not. Since bedding my chassis itā€™s almost 100% eliminated my need to adjust my zero over the course of 3 days at a match. Itā€™s been a significant improvement.
 
Iā€™d be happy to but none of mine are bedded. No one I have access to in the homie group has one bedded either. Iā€™d really like to test one to find out the outcome with a bedded chassis.

The only bedded rifles I have are both using a MK13 L shape recoil lugs. Those are without barrel pad due to the lug design.
 
spooledup,

How much bias to you have in your scope base and your mount? Could you tell me what each has individually?
 
spooledup,

How much bias to you have in your scope base and your mount? Could you tell me what each has individually?
So at least seven different sets of rings were used and 3 or 4 different rifles. Some of them being Bighorn which utilize dowel pins in the rail.

I donā€™t feel as if the issue is within the rail or rings.
 
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So at least seven different sets of rings were used and 3 or 4 different rifles. Some of them being Bighorn which utilize dowel pins in the rail.

I donā€™t feel as if the issue is within the rail or rings.
Putting bias in the base and mount pulls the erector tube away from the erector spring when zeroing the scope. These are important details.
 
The bullet was asleep, you woke it up by slapping it.

So now itā€™s flipping you the bird all the way to the target. Its tiny bullet middle finger is slowing it down and itā€™s hitting low.

Next bullet is wide awake and raring to go. Center punch.

Thatā€™ll be $5.
 
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I drop my gun into my positional bag to create a ā€œchannelā€ in the bag and have never had an elevation problem. I donā€™t slam it by any means, more of a controlled fall, but letting your gun drop into the bag is something the JTAC Okie boys teach and they seem to do just fine. I run a Kahles 525 DLR in Hawkins rings for my Dasher and the same for my 308 trainer, but with a Gen3 Razor.
When Iā€™m bored shooting service rifle I will shoot at my shotmarker at 600 from barricades, tires and so on and havenā€™t had this issue. So, maybe Iā€™m not using enough force to cause this? Iā€™ll try and cause this poi shift this Sunday when Iā€™m practicing. It was mentioned previously, but the thing that bothers me the most is folks carrying their 25lb rifle by their 3k+ scopes. I think that is just asking for a failure to occur. šŸ˜…
 
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Before I posted what I did earlier in the thread I knew w/o a doubt no one would believe me.
It's par for the course on this site.
One of the first thing I said was to "think".
I guess that must be old fashioned these days huh ?

Once you've fired 15-20 rounds look thru the bore, you'll see small bits of unburnt powder and random debris.....you all should know this w/o my having had to type it out.
If you slap the barrel hard enough all that shit goes to one side of the bore, same thing happens when you drop the rifle.
It has an effect, whether you choose to acknowledge it or not, denial doesn't make it go away.

We have a guy that has swapped barrels, swapped scopes and mounts, swapped chassis or stocks, yet the same problem is repeatable.
Huh, isn't that strange ?
He said the problem is slightly less with the old Loopy Mk4 fixed power......strangely enough I'll wager it's the lightest scope of them all by quite a bit.
Less inertia in the drop.....or is my mathing all fuxored ?

I'll wait for someone to get frustrated enough to actually chrono the shot after the drop.....and laugh my ass off.
 
If you slap the barrel hard enough all that shit goes to one side of the bore, same thing happens when you drop the rifle.
It has an effect, whether you choose to acknowledge it or not, denial doesn't make it go away.
Why doesn't that effect show up in a bedded chassis like @morganlamprecht tested? Why did it only happen in non-bedded chassis for him?
 
If Iā€™m following you correctlyā€¦what you mention is why I always fully seat all mating surfaces of rings caps and clamps before torquing screws to make sure they donā€™t tighten ā€œartificiallyā€ from small misalignments, friction, etc before fully seatingā€¦and are only held by the respective clamping forces best I can manage

Having an uneven clamp/cap/mount just takes the right impact to shift it/settle it

I always thought of it like when unbolting 2 pieces that slightly misalign making the bolt feel tightā€¦give one of the pieces a whack or relieve the pressure/misalignment and the bolt can spin freely with your fingers

Iā€™ve also used a small amount of grease in the past on rails/clamp mating surfaces to make sure theyā€™re able to slide together and fully seat before torquing, but I didnā€™t find issues leaving the grease out and just aligning by hand so I canā€™t say it helped, but it didnā€™t seem to hurt either

Correct. Grease along the top of the rail and on the clamping surfaces of the pic clamp often helps. If you pay attention (and it sounds like you definitely do), it does not hurt either. Some clamp designs are more susceptible to this than others.

ILya
 
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This has been an very interesting read and got me to thinking.
Awhile back I was in the garage and had one of my rifles in a tripod, I am 6'2" and to be at shoulder height the rifle is pretty high off of the floor.
My wife let my dogs out in the garage because they were annoying her whining at the door to get to me.
They started showing off trying to get my attention wrestling around with each other and knocked the tripod and rifle over.
Rifle bounced from the barrel tip first and then full weight down on the scope, it hit hard enough to to dent the scope shade and bent the elevation turret.
I figured for sure it was totally fucked but what the hell took it to the range to shoot it.
It was a little low and to the right but still grouped just fine so I was impressed but with the bent elevation turret I couldn't dial it back to were it was.
I thought to myself damn scopes have come a long ways durability wise and then I started reading this thread and have second guessed that.
 
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For nothing but zero retention, what's your scope rings or mount of choice? I don't think I need many features, I just want something that my scope will never shift in. Is there a top dog on just sheer clamping force or friction on the scope/rail?

Honestly, most good quality mounts when properly mounted work just fine: Area 419, Badger, Seekins, etc.

ILya
 
For nothing but zero retention, what's your scope rings or mount of choice? I don't think I need many features, I just want something that my scope will never shift in. Is there a top dog on just sheer clamping force or friction on the scope/rail?
Hawkins Precision is all I use for the most part nowadays.
 
This has been an very interesting read and got me to thinking.
Awhile back I was in the garage and had one of my rifles in a tripod, I am 6'2" and to be at shoulder height the rifle is pretty high off of the floor.
My wife let my dogs out in the garage because they were annoying her whining at the door to get to me.
They started showing off trying to get my attention wrestling around with each other and knocked the tripod and rifle over.
Rifle bounced from the barrel tip first and then full weight down on the scope, it hit hard enough to to dent the scope shade and bent the elevation turret.
I figured for sure it was totally fucked but what the hell took it to the range to shoot it.
It was a little low and to the right but still grouped just fine so I was impressed but with the bent elevation turret I couldn't dial it back to were it was.
I thought to myself damn scopes have come a long ways durability wise and then I started reading this thread and have second guessed that.

i had a rifle take a similar fall

said scope on that rifle came with the bungee style scope caps/covers...

pre fall, the scope covers fit between the objective and rail...post fall, it wouldnt fit

everything still felt tight, so i shot it anyways...zero had shifted like .5mil elevation and 1.5mil windage or something similar

the scope cover not fitting tipped me off something moved so i loosened the ring clamps to the rail and took the scope off, then reinstalled...the scope cap fit between the rail and objective again, and my zero moved back onto a 3/4" dot

at the time i didnt take it back apart to look for damage to the rail/ring clamps, but it held zero fine for the rest of the time i owned that rifle and it didnt take any other hard falls
 
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i had a rifle take a similar fall

said scope on that rifle came with the bungee style scope caps/covers...

pre fall, the scope covers fit between the objective and rail...post fall, it wouldnt fit

everything still felt tight, so i shot it anyways...zero had shifted like .5mil elevation and 1.5mil windage or something similar

the scope cover not fitting tipped me off something moved so i loosened the ring clamps to the rail and took the scope off, then reinstalled...the scope cap fit between the rail and objective again, and my zero moved back onto a 3/4" dot

at the time i didnt take it back apart to look for damage to the rail/ring clamps, but it held zero fine for the rest of the time i owned that rifle and it didnt take any other hard falls
The scope I mentioned is back in the factory box, I just need to send it back for repair.
They are pretty darn tough scopes, atleast in my mind.
I have seen two scopes in the past that held up fine on sporter 30-06 rifles and then moved to a 300wm have their pants pulled in part of a range session.
 
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Someone has to say it..

Sounds like AI had it figured out with a bonded chassis šŸ˜‚šŸ˜‚šŸ˜‚

Just busting chops and learning
 
Before I posted what I did earlier in the thread I knew w/o a doubt no one would believe me.
It's par for the course on this site.
One of the first thing I said was to "think".
I guess that must be old fashioned these days huh ?

Once you've fired 15-20 rounds look thru the bore, you'll see small bits of unburnt powder and random debris.....you all should know this w/o my having had to type it out.
If you slap the barrel hard enough all that shit goes to one side of the bore, same thing happens when you drop the rifle.
It has an effect, whether you choose to acknowledge it or not, denial doesn't make it go away.

We have a guy that has swapped barrels, swapped scopes and mounts, swapped chassis or stocks, yet the same problem is repeatable.
Huh, isn't that strange ?
He said the problem is slightly less with the old Loopy Mk4 fixed power......strangely enough I'll wager it's the lightest scope of them all by quite a bit.
Less inertia in the drop.....or is my mathing all fuxored ?

I'll wait for someone to get frustrated enough to actually chrono the shot after the drop.....and laugh my ass off.
Then why isnā€™t this a problem for everyone who drives or flys with a gun? Bumps and flights knocking around the unburnt debris to one side.
 
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Reeling them in.šŸ˜
 

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Anyone pull any pre/post measurements? If the barrel at the forend moved.....the numbers will tell you.
 
My wife let my dogs out in the garage because they were annoying her whining at the door to get to me.
They started showing off trying to get my attention wrestling around with each other and knocked the tripod and rifle over.
Rifle bounced from the barrel tip first and then full weight down on the scope, it hit hard enough to to dent the scope shade and bent the elevation turret.
Ah...so, did you have dog stew for dinner that night? lol
 
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Before I posted what I did earlier in the thread I knew w/o a doubt no one would believe me.
It's par for the course on this site.
One of the first thing I said was to "think".
I guess that must be old fashioned these days huh ?

Once you've fired 15-20 rounds look thru the bore, you'll see small bits of unburnt powder and random debris.....you all should know this w/o my having had to type it out.
If you slap the barrel hard enough all that shit goes to one side of the bore, same thing happens when you drop the rifle.
It has an effect, whether you choose to acknowledge it or not, denial doesn't make it go away.

We have a guy that has swapped barrels, swapped scopes and mounts, swapped chassis or stocks, yet the same problem is repeatable.
Huh, isn't that strange ?
He said the problem is slightly less with the old Loopy Mk4 fixed power......strangely enough I'll wager it's the lightest scope of them all by quite a bit.
Less inertia in the drop.....or is my mathing all fuxored ?

I'll wait for someone to get frustrated enough to actually chrono the shot after the drop.....and laugh my ass off.

Except he's shooting Kraft drills at 100yds. There's no amount of chrono speed that will affect elevation at 100yds. Well, there is.....but it would be a massive difference.

This has been tested to death with purposely slowing down rounds.
 
Snipershide 2023: "Rokslide drop/impact tests are stupid. Simple solution, don't drop your rifle. Also, these tests aren't lab controlled so the anecdotal data has no value."

Snipershide 2024: "I dropped my rifle and my zero shifted. Maybe we can collect data to see what's happening."

For what it's worth, I don't think it's the scopes, there is so much scrutiny on shock testing scopes by manufacturers these fays. I'd bet it's chassis bedding or barrel deflection during impact.
 
SnipersHide 2023: Rokslide drop tests are arbitrary, uncontrolled, not repeatable, and focused on a single personality. Letā€™s separate from personalities, refine the process, & standardize to isolate the variables & find the issue.

SnipersHide 2024 (this thread): itā€™s probably chassis/stock movement. Letā€™s move towards isolating the variables to find the issue.
 
SnipersHide 2023: Rokslide drop tests are arbitrary, uncontrolled, not repeatable, and focused on a single personality. Letā€™s separate from personalities, refine the process, & standardize to isolate the variables & find the issue.

SnipersHide 2024 (this thread): itā€™s probably chassis/stock movement. Letā€™s move towards isolating the variables to find the issue.
I can only speak from my sample size of one that I actually seen a small shift in zero that I know was from scope damage.
The action in the chassis slipping I feel very confident was not the issue.
Chassis is a XLR Carbon with action screws torqued to 65 in lbs, scope after impact had the elevation adjustment stem bent enough that the turret was visibly tilting to one side.
The zero shift was minimal and if I had no other choice could have finished a hunt with it, attempted to adjust the shift back to zero but the stem was bent enough to prevent that due to binding.
 
I can only speak from my sample size of one that I actually seen a small shift in zero that I know was from scope damage.
The action in the chassis slipping I feel very confident was not the issue.
Chassis is a XLR Carbon with action screws torqued to 65 in lbs, scope after impact had the elevation adjustment stem bent enough that the turret was visibly tilting to one side.
The zero shift was minimal and if I had no other choice could have finished a hunt with it, attempted to adjust the shift back to zero but the stem was bent enough to prevent that due to binding.
I donā€™t think anyone is arguing that scopes canā€™t or donā€™t lose zero.
 
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I donā€™t think anyone is arguing that scopes canā€™t or donā€™t lose zero.
Agreed was mainly commenting on the trend of comments regarding the action shifting in bedding or the chassis.
Properly bedded and torqued action screws or a good chassis inlet design negates that concern, that was my point.
Sorry could have been more clear on that one.
 
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Agreed was mainly commenting on the trend of comments regarding the action shifting in bedding or the chassis.
Properly bedded and torqued action screws or a good chassis inlet design negates that concern, that was my point.
Sorry could have been more clear on that one.
I didn't even consider unbedded chassis might shift but another thread got me interested and I think it's a lot more common than people believe. Phil Cashin has said a few times that unbedded chassis are way more susceptible to POI shift from impacts and having wandering zeros. I don't see why a chassis manufacturer would be incentivized to say that if it weren't true.
 
I didn't even consider unbedded chassis might shift but another thread got me interested and I think it's a lot more common than people believe. Phil Cashin has said a few times that unbedded chassis are way more susceptible to POI shift from impacts and having wandering zeros. I don't see why a chassis manufacturer would be incentivized to say that if it weren't true.
That was why I said a "Good" chassis inlet design.
Not pointing fingers at any but I can attest to the inlet on my XLR carbon chassis as my rifle took a pretty hard hit and the only thing that shifted was my zero on a damaged scope.
I still haven't touched my action screws since before the rifle was knocked out of a tripod onto a concrete floor, just pulled the damaged scope put another one on and have been shooting it every since then.
Manufacturers do a pretty damn good job considering all the variations of actions and new models coming out constantly but I'm sure there are some small amount of instances that cause issues.
 
Seems I have a scope issue times seven scopes. It also seems like this is a legit issue. So, with that said I have a question for you dudes. Has anyone else seen an impact shift when dropping the rifle on a bag and taking a shot?
Do you wear glasses and/or have an Astigmatism with your dominant eye?