hello everyone i have a new vortex viper hs lr and have been experiencing problems with my windage drifting. what i mean by that is i sighted my rifle in on a relatively calm day with little to no cross winds at 200 yards and zeroed my turret (this is the model that doesnt have the tactical windage turret)... Now a month later after 4 sessions at the range my windage turret is now set 6 moa right off from the origional zero on a calm day. i dont know why my zero has drifted 6 moa right of the origional zero. thanks for your help.
vortex viper windage drifting
- Thread starter moklr
- Start date
- Status
It could be the scope. Loose base or rings...possible. Have you taken it out of the stock since sighting in? If you've cranked in back into the stock with different in/lb of torque that may do it. You've got to start to eliminate the possiblilites one at a time.
rcmodel
Member in memoriam
Need more details.
What is the rifle?
AR-15 Flat Top?
Bolt-action with separate bases?
Wood stock?
Etc.
rc
What is the rifle?
AR-15 Flat Top?
Bolt-action with separate bases?
Wood stock?
Etc.
rc
vortex viper windage problem.
thanks for responding so quickly. the rifle is a bolt action remington 700 5r milspec and it has seperate bases. i have taken the stock off however i re-torqued it to 65 in lbs and my poi didnt start drifting untill after that. what i mean is it was holding a zero fine after i took the stock off. then one day it just started drifting i check bases and mounts everything is tight.
thanks for responding so quickly. the rifle is a bolt action remington 700 5r milspec and it has seperate bases. i have taken the stock off however i re-torqued it to 65 in lbs and my poi didnt start drifting untill after that. what i mean is it was holding a zero fine after i took the stock off. then one day it just started drifting i check bases and mounts everything is tight.
Lafitte
Member
Have you made any elevation changes?
Lafitte
Lafitte
farmerboy78
Member
- Joined
- Jan 19, 2010
- Messages
- 946
So you completely removed the scope and rings to check the tightness? Has the act u all turret moved the 6 moa or does the zero seem to have moved and the turret sitting still?
vortex viper windage problem?
i did have the scope off the rifle however the zero didnt start to shift till well after that. i only took the scope off when i noticed there was a problem. the scope seems to hold a zero when im at the range then i come back another day and the poi has shifted so i have to re adjust and now after readjusting a couple sessions at the range im am now 10 clicks to the right of my origional zero.
ps. i called vortex today any they didnt seem to think there was a problem with the scope. the guy i spoke to said he thought my rings may have been overtightened. i do not think this is the problem though as i am very careful not to over tighten things as i would hate to dammage my scope. thanks for all your help.
i did have the scope off the rifle however the zero didnt start to shift till well after that. i only took the scope off when i noticed there was a problem. the scope seems to hold a zero when im at the range then i come back another day and the poi has shifted so i have to re adjust and now after readjusting a couple sessions at the range im am now 10 clicks to the right of my origional zero.
ps. i called vortex today any they didnt seem to think there was a problem with the scope. the guy i spoke to said he thought my rings may have been overtightened. i do not think this is the problem though as i am very careful not to over tighten things as i would hate to dammage my scope. thanks for all your help.
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Scope internals
Mounts
Rings
You can try putting the scope on another rifle (swap it on to another rifle with the same sized rings). This can identify if the scope is the problem.
If you know that the scope is good then check the mounts by firing a few shots for a group, tap the front or the rear mount with a small punch and hammer and fire another group. If the group moved then that mount is loose. Do the same test for the other mount. Tap the mounts on both the left and right sides but only one way or the other for each test, put tape on the mounts where you will be tapping with the punch. Check the screws that hold the mounts to the barrel to make sure that they fit the countersink properly. Check the centerline of both mounts, they absolutely need to be on the same line. Make sure that the mounts fit the top of rifle solidly, they should not rock.
Check the rings for a tight fit to the mount. Check the centerline of the rings and make sure that their on the same line and that they are on the same line as the mounts. Make sure that the scope's tube is touching at least 80% of the rings.
I've seen rings that were not holding the scope tube properly because the rings were out of round, rings that didn't fit the rails properly, and others that were off center. I had one set of aluminum mounts that fit improperly and the screws were pulling through the mounts.
Mounts
Rings
You can try putting the scope on another rifle (swap it on to another rifle with the same sized rings). This can identify if the scope is the problem.
If you know that the scope is good then check the mounts by firing a few shots for a group, tap the front or the rear mount with a small punch and hammer and fire another group. If the group moved then that mount is loose. Do the same test for the other mount. Tap the mounts on both the left and right sides but only one way or the other for each test, put tape on the mounts where you will be tapping with the punch. Check the screws that hold the mounts to the barrel to make sure that they fit the countersink properly. Check the centerline of both mounts, they absolutely need to be on the same line. Make sure that the mounts fit the top of rifle solidly, they should not rock.
Check the rings for a tight fit to the mount. Check the centerline of the rings and make sure that their on the same line and that they are on the same line as the mounts. Make sure that the scope's tube is touching at least 80% of the rings.
I've seen rings that were not holding the scope tube properly because the rings were out of round, rings that didn't fit the rails properly, and others that were off center. I had one set of aluminum mounts that fit improperly and the screws were pulling through the mounts.
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climbnjump
Member
Is it this:
or this:
If you're still shooting at 200 yards, then 6 MOA is about a 12 inch shift in zero. However, 10 clicks would be about a 5 inch shift since the windage on that scope is 1/4 MOA per click. I guess both are bad, but one is certainly worse than the other. And please forgive me for asking, but you are using the same ammo now that you used to zero with, right?
Also:
If the zero didn't start to drift until AFTER you had removed and replaced the scope, but you didn't remove the scope until AFTER you noticed there was a problem, then what was the original problem?
I agree with one of the other commenters, it would be a good idea to remount the scope on a different rifle with different rings and different bases to try to isolate the problem to the scope. If you don't have another rig that would work, perhaps a buddy might?
or this:
If you're still shooting at 200 yards, then 6 MOA is about a 12 inch shift in zero. However, 10 clicks would be about a 5 inch shift since the windage on that scope is 1/4 MOA per click. I guess both are bad, but one is certainly worse than the other. And please forgive me for asking, but you are using the same ammo now that you used to zero with, right?
Also:
.
If the zero didn't start to drift until AFTER you had removed and replaced the scope, but you didn't remove the scope until AFTER you noticed there was a problem, then what was the original problem?
I agree with one of the other commenters, it would be a good idea to remount the scope on a different rifle with different rings and different bases to try to isolate the problem to the scope. If you don't have another rig that would work, perhaps a buddy might?
re vortex viper problem
it is 10 clicks or 5 inches off the origional zero and yes i am still shooting at 200 i must have counted wrong sorry for the mistake. Quote:
i did have the scope off the rifle however the zero didnt start to shift till well after that. i only took the scope off when i noticed there was a problem....typo sorry i had the scope off the rifle to give it a good cleaning i then put it back on went to the range and everything was fine...then over the course of then next 2 or 3 range trips my zero shifted. i do have another rifle to mount it on maby ill do that this time but itll probably take a few trips to the range as it seems to be drifting very slowly. oh and yes i am shooting the same ammo same powder same bullet everything
it is 10 clicks or 5 inches off the origional zero and yes i am still shooting at 200 i must have counted wrong sorry for the mistake. Quote:
i did have the scope off the rifle however the zero didnt start to shift till well after that. i only took the scope off when i noticed there was a problem....typo sorry i had the scope off the rifle to give it a good cleaning i then put it back on went to the range and everything was fine...then over the course of then next 2 or 3 range trips my zero shifted. i do have another rifle to mount it on maby ill do that this time but itll probably take a few trips to the range as it seems to be drifting very slowly. oh and yes i am shooting the same ammo same powder same bullet everything
Did you locktite the screws?
If the mounts and rings don't align on the same centerline then they will rock back and forth under recoil, you can't see the movement and probably can't feel it but then you can't apply the same kind of force that recoil does (several hundred pounds per square inch). Over time that slight movement will cause damage to the screws, mounts, rings and there will be larger and larger movement due to a misfit of the fasteners and their corresponding contact areas. Locktite simply helps counter the poor fit by adding extra holding strength to the screws which reduces the chance of the parts moving to begin with.
If the mounts and rings don't align on the same centerline then they will rock back and forth under recoil, you can't see the movement and probably can't feel it but then you can't apply the same kind of force that recoil does (several hundred pounds per square inch). Over time that slight movement will cause damage to the screws, mounts, rings and there will be larger and larger movement due to a misfit of the fasteners and their corresponding contact areas. Locktite simply helps counter the poor fit by adding extra holding strength to the screws which reduces the chance of the parts moving to begin with.
re vortex viper problem
i put blue loctite on the screws that hold the bases not on the screws that go into the rings. i hope it doesnt have anything to do with things not lining up like holes being drilled off center since this is a new rifle.
i put blue loctite on the screws that hold the bases not on the screws that go into the rings. i hope it doesnt have anything to do with things not lining up like holes being drilled off center since this is a new rifle.
So I think I'd send the scope to factory to be checked (just complain that it's not holding zero, that's a common problem with some of the lower end Vortex scopes) and have a machinist or gunsmith check the holes for proper positioning (I've seen the holes screwed up from the factory).
If the holes are off it can fixed without damaging the receiver.
Remember, on most rifles it only takes about .008" of movement in the sights to create about an inch of impact error at 100 yards. 2.5 MOA would be about .020" movement in any of the mounting parts or the lenses inside the scope. It doesn't take much movement to see the effect on the point of impact and recoil forces can move ill-fitting metal parts over time.
I need to clarify, it only takes about .008" of movement in the sights of a iron sighted rifle but it's worse for scopes because the lenses are closer together than iron sights are. Scopes only need to have an offset of around .004" between the eye lens and the objective lens for one MOA error, that would mean that an offset of around .010" has occurred.
If the holes are off it can fixed without damaging the receiver.
Remember, on most rifles it only takes about .008" of movement in the sights to create about an inch of impact error at 100 yards. 2.5 MOA would be about .020" movement in any of the mounting parts or the lenses inside the scope. It doesn't take much movement to see the effect on the point of impact and recoil forces can move ill-fitting metal parts over time.
I need to clarify, it only takes about .008" of movement in the sights of a iron sighted rifle but it's worse for scopes because the lenses are closer together than iron sights are. Scopes only need to have an offset of around .004" between the eye lens and the objective lens for one MOA error, that would mean that an offset of around .010" has occurred.
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no i cannot see any wear marks inside the rings. ive looked for spots that are worn or spots that could cause movement and i cant see anything that would cause .020 movement. i would like to have a gunsmith take a look at it but i dont know of any (i live on long island) closest one would probably be in pa somewhere. thanks for all the ideas
If the rifle has front and rear iron sights then you can simply tie some fishing line between the two and carefully measure or simply eyeball the holes in relation to the fishing line.
If it doesn't have iron sights then a simple (and less accurate) process is to buy a piece of round stock or metal tubing (from the hardware store) that will fit inside the rings (call it an alignment gauge). Removing the scope and installing the gauge in it's place will allow you to compare the gauge to the barrel and compare the fit of the rear ring to the front ring. The gauge needs to be long, the longer the better but no more than the barrel length. If you have a set of 20 MOA mounts you might want to make the gauge about half the length of the barrel plus the distance between the rings. It also helps if the gauge can be turned on a lathe so that the portion that would be over the barrel is the same diameter as the barrel but it's not necessary. If you can get the gauge the same diameter as the barrel it would be easier to estimate it's position along the sides of the barrel. Regardless, if you look at the gauge from the muzzle end of the rifle you will be able to see if it's offset to the left or right of the barrel.
If you install the gauge in the forward ring (with the gauge clamped by both rings halves) you can measure or eyeball the gauge as compared to the barrel. This will help you determine if the front ring/mount/holes are aligned with the barrel, if the gauge looks aligned with the barrel (as you look from the muzzle toward the receiver) then the front ring/mount/holes are aligned with the bore. Clamp the gauge in the front ring first to check it's alignment with the barrel and then do the same using the rear ring with the top half of the front ring removed. The gauge should still be in alignment with the barrel and it should also fit the bottom half of the front ring properly. Installing the gauge in to both rings will help identify if the rings are aligned to each other which also indicates whether the mount holes are aligned. Take the top of the rings off of both rings and install the gauge in to the bottom halves, the gauge should settle in to both rings solidly, you shouldn't be able to rock it in any direction. If the gauge rocks and you've already verified that the front ring is properly aligned with the barrel then that means that the back ring has an alignment problem.
One other test is to verify that the mounts fit properly. You can do that by loosening the screws for the mount by backing them out no more than two turns. Do this on one mount at a time. Once the screws have been loosened try to rock the mount, it shouldn't. If it does rock then either the curve on the bottom of the mount isn't properly shaped or the holes don't line up, inspection should prove which is the case.
If it doesn't have iron sights then a simple (and less accurate) process is to buy a piece of round stock or metal tubing (from the hardware store) that will fit inside the rings (call it an alignment gauge). Removing the scope and installing the gauge in it's place will allow you to compare the gauge to the barrel and compare the fit of the rear ring to the front ring. The gauge needs to be long, the longer the better but no more than the barrel length. If you have a set of 20 MOA mounts you might want to make the gauge about half the length of the barrel plus the distance between the rings. It also helps if the gauge can be turned on a lathe so that the portion that would be over the barrel is the same diameter as the barrel but it's not necessary. If you can get the gauge the same diameter as the barrel it would be easier to estimate it's position along the sides of the barrel. Regardless, if you look at the gauge from the muzzle end of the rifle you will be able to see if it's offset to the left or right of the barrel.
If you install the gauge in the forward ring (with the gauge clamped by both rings halves) you can measure or eyeball the gauge as compared to the barrel. This will help you determine if the front ring/mount/holes are aligned with the barrel, if the gauge looks aligned with the barrel (as you look from the muzzle toward the receiver) then the front ring/mount/holes are aligned with the bore. Clamp the gauge in the front ring first to check it's alignment with the barrel and then do the same using the rear ring with the top half of the front ring removed. The gauge should still be in alignment with the barrel and it should also fit the bottom half of the front ring properly. Installing the gauge in to both rings will help identify if the rings are aligned to each other which also indicates whether the mount holes are aligned. Take the top of the rings off of both rings and install the gauge in to the bottom halves, the gauge should settle in to both rings solidly, you shouldn't be able to rock it in any direction. If the gauge rocks and you've already verified that the front ring is properly aligned with the barrel then that means that the back ring has an alignment problem.
One other test is to verify that the mounts fit properly. You can do that by loosening the screws for the mount by backing them out no more than two turns. Do this on one mount at a time. Once the screws have been loosened try to rock the mount, it shouldn't. If it does rock then either the curve on the bottom of the mount isn't properly shaped or the holes don't line up, inspection should prove which is the case.
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SilentStalker
Member
Ok, let me see if I can help here. If you are fairly confident its not the rings, it was a factory drilled receiver job, you loctited the screws on the rings,etc. then I must ask the simple question of whether or not you actually checked the torque on the action screws? Other than that, is this a reg stock or a chassis system? if its a reg stock is it possible that it was bedded and the bedding has shifted? is the barrel threaded? If so, are you running a brake? Sometimes, I have found that taking a brake on or off will cause a shift. It really shouldn't but I have one rifle that seems to do this. Are you 100% positive that you aren't somehow torquing the rifle when firing?
One more comment about the alignment gauge idea.
You can avoid messing with finding a tube or rod that fits your rings by simply buying the proper sized alignment kit from Kokopelli Products. The page I linked to is a discussion about how his alignment tools work better and under the heading of "WHY THE KOKOPELLI SCOPE BARS WORK" he provides pictures that will demonstrate the gauge concepts I described.
Here is the idea of checking the front ring
And this is an image of a bad alignment between the rear ring and the front ring
This is a proper alignment
You can avoid messing with finding a tube or rod that fits your rings by simply buying the proper sized alignment kit from Kokopelli Products. The page I linked to is a discussion about how his alignment tools work better and under the heading of "WHY THE KOKOPELLI SCOPE BARS WORK" he provides pictures that will demonstrate the gauge concepts I described.
Here is the idea of checking the front ring
And this is an image of a bad alignment between the rear ring and the front ring
This is a proper alignment
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