Why does my zero keep wandering?
 

Every time I go shooting my zero has wandered a few inches at 200 yards. The groups are always great (often 2" @ 200 yds, which is good for my bad eyes), but they keep wandering. I' ll re-adjust it a few clicks to dead on, but the next visit the group has moved.

This also happens on the same day when I readjust for 600 or 1,000 yards, then move the scope back to 200 yds afterwards. Temperature doesn' t seem to be a factor, so I' m wondering what' s causing this.

Here' s the set-up: Model 70 Classic Stainless in .300 Win Mag with BOSS at the factory setting. 2.5-8 Vari-X III. 180 gr Sierra ProHunters ahead of 75 gr of RL22 (2950-3000 fps). (The problem also occured when I was shooting 2850 fps with 70 gr of IMR 4831.)

I sent the scope back to Leupold, who found defective internals, which they said they replaced. The problem continued. I also switched out the factory plastic stock with a glass bedded HS Precision stock, but the problem remains.

Any suggestions where to go next? Sure would appreciate your input. (I still suspect the scope, but I' m not an expert at this stuff.) I' m spending a lot on bullets and powder!

RE: Why does my zero keep wandering?
 

Years ago I had a Remington semi-auto .22 that would do the same thing. You could zero the iron sights dead on at 50 yards, get it out the next day and and it would shoot the same 1.5" group 6 inches in another direction. One day it would go right, the next it might go left, up, or down. Put a scope on it and did the same thing. Mine didn' t have anything to do with weather either. I finally sold it for $50 at a gun show. My dad had the exact same rifle, only 10 years older. His will hit dead on the bullseye everytime. Go figure.

RE: Why does my zero keep wandering?
 

Since its only a couple of inches at 200 yds, I would say you are probably dealing with paralax. If you have a scope with adjustable objective, put it on and see what happens. Or just try shooting the 2.5x8 at the yardage its set to be paralax free at, which I think will be 150 yds. My first guess.

RE: Why does my zero keep wandering?
 

The problem you described seems very minor to me.......it' s a couple inches at 200 yards?.....and the groups are still good but off center?......this seems like simply relieving of stress in the barreled action to me.....it' s a normal and natural thing that goes on for up to five years.....it doesn' t happen over night.....it' s a change that happens over several months.....relax.....it' ll be ok!!

Damn few riflemen can detect that stress relieving.....congrats.....you' re one in a thousand.

RE: Why does my zero keep wandering?
 

Stress Relieving?takes a couple years to stop? A natural thing?Wow my guns have shot well from the start or I found out why and fixed them,maybe Savages don' t need to stress relieve themselves(pillar bedding and floating barrels).I would suspect the scope since they found problems and changed some internals already.Parallax,unless you hold your eye in exactly the same position each time won' t result in tight groups slightly off center,but will tend to scatter your shots slightly.If possible try another scope of some kind so you can eliminate the scope as a possibility.At the same time if you use the same mounts it can eliminate them also.Synthetic or wood stock?

woods

RE: Why does my zero keep wandering?
 

Well, think there has been one thing that you said was found defective. I would try a friends scope that is tried and trusted. Also, maybe the way the scope is mounted. If your using dovetails for the front on a two peice base, and adjusted the windage screws in the back alot, this puts alot of stress on the scope while it is tightened down in the front.

I really don' t see zero being off from the gun or barrel stress' s unless your taking the action out of the stock every time. That might do it.

RE: Why does my zero keep wandering?
 

BTM,
I am assuming that your H-S stock is free floated, so I would eliminate that. If it is not free floated, get it free floated. It could be the factory barrel does indeed have stress in it, due to not being properly stess releived from the factory. It could also be due to parallex, but with a 2.5-8x scope, you can' t do much about it.

There again, it very well may be changes in the weather conditions. Changes in air temps, barometric pressures, humidity, winds, etc., always have some kind of effect on a bullet' s trajectory and flight, some times minor, some times major effects. As the ranges increase so do the amount of the effect of the atmospheric conditions.

RE: Why does my zero keep wandering?
 

Thanks for your input, gents!

Scope is focused for 150, and I don' t see how paralax could be the cause of such radical shifts in POI. Rifle is 5 years old and has had 1500-2000 rounds through it, so it' s probably stressed relieved and then some. Barrel is free floated. I' ve done enough shooting in enough different conditions to have ruled out atmospheric conditions.

I think it' s time to send the scope back to Leupold.

RE: Why does my zero keep wandering?
 

Hey BTM, considering the wide geography of people on these forums we' re practically neighbors. I' m curious what type of hunting you do, and what general area you go to. A friend and I have recently purchased rifles and just joining the sport. Have to submit our info and try to get a deer tag soon. We' re also kicking around the idea of imposing on my relatives back east, hunting in Pennsylvania, Kentucky, or Georgia.

RE: Why does my zero keep wandering?
 

Calnewbie: I' m primarily a bowhunter, but a few hogs and deer have fallen to my firearms. If you want to get started locally, there are plenty of places to hunt hogs in Central CA for not too much money, plus the eatin' is great! Wish I had someone back east who' d let me hunt on their land.

If you want more info re. hogs, give me a buzz: [email protected]

RE: Why does my zero keep wandering?
 

what condition is the barrel in , inside the bore , barrels do wear out and need replacing after so many rounds , especially in a high velocity round like a .300 mag , that might be something to get checked

if the barrels in good shape and it' s stress relief , and it really bothers you have you considered changing the scope mount style and having it mounted on the barrel itself , like a scout rifle , just a thought :D:D

RE: Why does my zero keep wandering?
 

just wanted to add , that if you go for a scout rifle style scope mount you' ll , have to get a new scope , a long eye relief scope. you probably allready know that but i just added it just in case :D:D

RE: Why does my zero keep wandering?
 

Whelen: The barrel shoots great groups; they just don' t stay consistent. (The other day I dropped five shots inside 3.5" at 400 yds.)

I gave up on scout scopes after learning (the hard way) that you lose about 20 minutes of shooting light at the start and end of every day.

RE: Why does my zero keep wandering?
 

Come up to Maine and I' ll point you at more land to hunt than you have time for.No shortage of available land to hunt and lots of elbow room also.Deer kill is low but about 25% are mature bucks with a good chance of a 200# dressed buck if you connect.I still say try another scope,unless the stock is twisting the action and stressing it when tightened, the scope just sounds like the culpirt.A synthetic stock is pretty much unaffected by weather conditions and parallax just don' t sound like that much of a factor at 200yds.

woods

RE: Why does my zero keep wandering?
 

My brother and I had the same trouble trying to site in my fathers shotgun at 50 yards. The groups kept moving. Now granted it was just a cheap Mossberg 500, but still, the groups kept moving!

Towards the end we were very frustrated, and almost fighting over who had to take the next shot, as it was absolutely beating us up. Around the 50th shot we realized the rings were a little loose. We were trying to blame us, instead of the equipment, but it just ended up being the mounts.

I' d deffinately try a new scope first, a trusted friends or another proven you have, and then try new mounts if that doesn' t work.

RE: Why does my zero keep wandering?
 

Sound like from your description you are moving your scope setting fairly often.
If you leave your scope setting alone for 4 or 5 trips to the range do your groups settle down.
When you adjust your scope make sure you check it after adjusting it to make sure the zero actually moved to where you think you moved it,
If you are adjusting your scope after you finish a shooting session, you will have to recheck and adjust your zero each time you start your next shooting session.
Sometimes when you adjust your scope setting it may take a shot or two to settle in, especially if it is cold. Also returning your scope to the previous setting may not actually move your point of impact back to the exact previous spot.
Try leaving the scope settings alone for awhile and see if your points of impact don' t settle down.
If they do settle down your scope is ok, if not then go on to loose mounts on your scope, you cannot tighten your scope down to tight either, shoot from a dirty barrel for a few sessions, cleaning residue in your barrel can affect impact, check the bolts holding action to stock too tight or too loose can have an impact.
Are you shooting the same ammo each time, change anything in your reloads or factory ammo and impact will shift.

RE: Why does my zero keep wandering?
 

Noway:Thanks for the advice. The problem has existed through two separate mounting systems (Leupold and Weaver). Both were installed tight, which further leads me to believe it' s the scope that' s bad. As far as adjusting, the Vari X III has click adjustments, so they should move precisely with every click.

I' ve owned other rifles before, and have never had to let them " settle down." (I know that bullets move a little slower in cold temps, but the problem goes beyond just hitting an inch or two low when it' s cold. ) Once I zeroed them, they didn' t have to be re-adjusted every time I went to the range or after I' ve readjusted it the same day in order to shoot a different distance. I' ve even heard that " boxing" a scope (i.e., shooting a 12" square) is the sign of a good scope.

The last time I shot, I again set the rifle to dead on. Will return to the range next week and see where it hits. If it' s not dead on, Ill send the scope back to Leopold and let you gents know what happens then.

RE: Why does my zero keep wandering?
 

It' s extremely difficult to understand how the scope is a problem when you' re shooting 2" groups at 200 yards..........

Regarding the possibility of a worn out barrel, even a .300 mag or even a .220 Swift will shoot well for more than 5000 rounds if they' re not shot hot and cleaned well regularly (50 rounds)......difficult to shoot a .300 mag hot....usually they are fired three times max in use!!!

I' ve owned Win 70s, Rem 700s, Ruger77s, Weatherby mark Vs, Sakos, Mausers, Browning A bolts, you name it.....and I' d not complain over a gun that shot 2" groups at 200 yards and the point of impact changed a couple inches annually......even in a few weeks.....It' s why we sight them in before every hunt.

I' ll repeat this.....most folks don' t have a gun good enough or are capable to detect the subtle changes.

A change of even .0005 anywhere in that gun can cause a few inches of impact change at that distance. Do you have a steel receiver and an aluminum tube scope? Want to guess what a few degrees temp makes in thermal expansion of that system.....

RE: Why does my zero keep wandering?
 

BTM,
I can see why you would be frustrated.
I also have varix III' s on my rifles.
In a perfect world when you adjust your scope 10 clicks up and 10 clicks down your point of impact will move back and forth to the same spot.
Unfortunately that is just not what always happens. Maybe for some people this works but it has never been my experience, expecially shooting at distances over 200 yards.

If you are adjusting your scope at the end of your shooting sessions and don' t check to see where your zero actually moved to and then when you go out to shoot again the zero did not move to where you expected it to then I am not surprised.

Even with a vari x III you have to actually check your zero and fine tune it to make sure the adjustments moved the zero to where you want it. Especially at 200 yards and further out.

Try leaving your adjustments where they are for awhile and see if you still get point of impact changes.
Good luck!

RE: Why does my zero keep wandering?
 

BTM, besides all the other possibilities mentioned, the most obvious is the way you are resting the rifle on the bags. With sporter weight rifles and hard kicking calibers, its not easy to hold the rifle exactly the same from one session to another. Try moving the spot on the forearm where the bag is contacting it. The amount of downward pressure you exert will also cause a slight shift in zero. These things are much easier to determine than sending a scope back.

RE: Why does my zero keep wandering?
 

Vapodog and Noway: Thanks again. Maybe I' m too idealistic expecting to not have to re-sight a rifle before every shooting session, but I have guns that never change zero (as do my friends). Plus, even if I did have the luxury of sighting in before a hunt (which usually impractical and noisy at hunting camp), it still doesn' t explain why the rifle changes during the same day. I have a friend who' s a police sniper, and he says he' d chuck any rifle that did what mine was doing. (His duty weapon is nothing fancy, either; just a heavy barreled .308 M700).

Larry338: I' d also pondered how I rested the rifle (great minds think alike, right?), but I kinda doubt it for the following reason: I often alternate rifles when to let the barrels cool. I' ll shoot one shot out of the .300, then lay it aside while shooting something else, then repeat for a five-shot group out of both rifles. (I know that' s not proper benchrest procedure, but it eases the boredom of waiting for a barrel to cool.) If anything, such a practice would lead to large groups, but it still shoots tight groups. But later in the day (no temp change) or after I' ve zeroed for a different distance, it' ll shoot several inches off.

Right now, I' d rather have a 2 MOA rifle that holds zero day in and day out that my sub MOA rifle with a wandering sero.

Thanks again for all of your input. A mechanic buddy has a great saying: " It' s alway' s something simple." When I find the answer, I' ll probably kick myself.

RE: Why does my zero keep wandering?
 

Yeah, that sounds like a mighty perplexing thing your rifle is doing. To get one acting like that I would think something is moving. Not sure what though since when things move typically, they dont produce good groups in different places. I give up. Its like your buddy says, the answer is easy, you just dont know what it is yet.

RE: Why does my zero keep wandering?
 

I would recommend a new scope for that sucker. Even with BOSS, that rifle has some recoil, and the main complaint about those Leupolds is that they cannot hang on to rifles that kick. They have their guts busted out by thumpers. Got a Burris for my 45/70, that thing kicks like a mule and that scope is one tough nut. Dead on all the time.

RE: Why does my zero keep wandering?
 

Guys, for a Vari-X III, it should come back to zero every time. I use them with target knobs at long distances. And if it doesn' t go back to zero, it gets sent back to leupold. Which I have done. Here is a test i did suggested by some benchresters.

Shoot a group, move up 6MOA and to the left/ (or right) 6MOA. Shoot another group. Move down 12MOA, another group, to the right (or left) another 12MOA and another group, up 12MOA, another group. Then put back to the original position over 6MOA and down 6MOA. It should be a box, and come right back to zero. But it takes around 18 or so bullets. But its fun to test out your scope.

I already sent one back over this. If your getting close to the end of adjustment of your scope too, it can fail this test. Thats the reason I try to center the scope to get the most adjustment.

RE: Why does my zero keep wandering?
 

Have you tried a different, proven, trusted scope on the rifle, so you could at least rule out the rifle or the scope? It would be a shame to send the scope back twice and later find out it was the rifle, or something else.

Jeff...U.P. of Michigan

RE: Why does my zero keep wandering?
 

NorthJeff: I' ve been thinking the same thing, but I don' t have a non-Leupold scope to check it with. But that may change: I' ve been eyeing one of those Kahles 3-9 scopes with the hashmarks for different distances (DPS or something like that). If the problem turns out to be the scope, Leupold owes me a lot of money for wasted ammo!