Scope problem

[N80]

It is a bolt action and I do have a gun vise. I've been thinking along the same lines as you about how to figure out what the problem actually is. The first thing I'm going to do is shoot it with the old scope back on it. If it shoots properly that will pretty much indicate that it is the Zeiss that is defective.

But, if I put the defective Zeiss on a gun and bore sight it, I don't think there would be a way that I could duplicate the shock of recoil without bumping it around and taking the bore off of its point of impact. In other words, if I bump it hard enough to duplicate the recoil, then the barrel isn't going to be pointed in the same place.

I'm pretty sure this scope has a lifetime warranty but I'm just stumped as far as figuring out a way to prove that it is actually the scope.

 

[nybirdman]

I would send it in,all the scope manufacturers are very good about repair/replacement.Are you "tapping" the scope after adjustment?You need to "tap it lightly" with the back of a screw driver to set the adjustments.If not the recoil will move it and you will be chasing all day.

 

[Egon]

I wonder how good those laser bore sights are? Most of the time I can bore sight by eye and get close enough to sight the gun in in just a few rounds. What I'd really like to know is how do I know if this scope is defective with it off the rifle?

Bore sight is almost like a peep sight.

 

[N80]

I would send it in,all the scope manufacturers are very good about repair/replacement.Are you "tapping" the scope after adjustment?You need to "tap it lightly" with the back of a screw driver to set the adjustments.If not the recoil will move it and you will be chasing all day.

I often do that, just because I remember seeing my Dad do it. But when I think about it i'm not sure it makes any sense. Especially with the Zeiss it has distinct clicks with each adjustment. Not sure why tapping would move or 'set' anything in a modern scope. And I often forget to do this on my other guns and there is no chasing of impact points.

But, even if it IS necessary to tap the scope to set the adjustment, in this case I do not think it is the problem because the last four shots were without any adjustments in between. Each shot climbed about an inch or two above the previous shot.

I'm still curious if an increasingly hot barrel that was somehow binding on a contact point in the stock could do this. I'd put 10 or 12 rounds through it in pretty quick succession. Seems unlikely.

 

[EE_Bota]

I often do that, just because I remember seeing my Dad do it. But when I think about it i'm not sure it makes any sense. Especially with the Zeiss it has distinct clicks with each adjustment. Not sure why tapping would move or 'set' anything in a modern scope. And I often forget to do this on my other guns and there is no chasing of impact points.

But, even if it IS necessary to tap the scope to set the adjustment, in this case I do not think it is the problem because the last four shots were without any adjustments in between. Each shot climbed about an inch or two above the previous shot.

I'm still curious if an increasingly hot barrel that was somehow binding on a contact point in the stock could do this. I'd put 10 or 12 rounds through it in pretty quick succession. Seems unlikely.

I think the screws have a minor amount of slop and there are springs inside pushing in a certain direction to make sure that slop is always taken up. It could be this is only for low end scopes, though.

Inside a Variable Power Riflescope - YouTube

It looks like the type of spring used has to have one end slide. Perhaps the tap eliminates the possibility of sticking on that end.

 

[jbooth]

Bore sighting can be improved somewhat by chamberiing a fired case with the primer pushed out and looking through the primer flash-hole. Not for old eyes and sometimes works better at night looking a a small light. A carboard box with V's cut in opposite sides will hold a rifle steady enough to bore sight when a rifle rest is not available.

 

[nybirdman]

Point of impact can surely change from an increasingly hot barrel.Especially a light weight sporter barrel.Time consumeing but try it out of a cold barrel,that's the one that counts.There is also a one shot site in method,but requires a good gun vise.
Shoot and without moving the gun move the scope to the bullet hole.Have you checked your action screws?

 

[sshaw]

I think N80 has already proven the Zeiss scope is the problem. He mounted the scope on a rifle that held zero fine with a Leupold scope, and the same rifle doesn't hold zero with the Zeiss. Plus, he said he recalled the Zeiss having problems in the past. I'd remount the Leupold and send the Zeiss back for service.

As for the turrets reaching the end of their range of motion... I have several Leupold scopes and their instructions say to recenter the turrets prior to mounting the scope on a different rifle. This ensures you have the widest range of adjustment left after sighting in. To center, you turn the turret all the way to one side, then turn it all the way to the other side while counting clicks, then turn it back half the number of clicks. Might not work on other brands though. If they don't have stops at the end, something could come unscrewed like EE_Bota mentioned.

After centering the turrets, you should then use a boresighter and align the scope crosshairs with the bore, using whatever adjustments are available on the scope base before using the turrets.

I use a laser boresighter from Site Lite that's like the one texasjohn pointed out. It works great. It has a magnetic arbor that inserts into the barrel and a laser pointer that projects a red dot onto the target. You insert the boresighter, aim at a target about 25 feet away, look for the red dot on the target through the scope, then adjust the scope so the crosshairs align correctly. Because scopes are usually mounted about 1.5" above the centerline of the bore you should adjust the crosshairs to be about 1.5" above the laser dot.

The Site Lite setup has worked very well for me mounting numerous scopes. Once I'm on the range it only takes a few clicks to fine tune things.

This is the one I have:

Cabela's: Site Lite SL-100 Boresighter

 

[N80]

Well, it isn't the scope. I put the old scope on it and the smallest group I could get at 100' is about 8". And I think I need to comment on something sshaw said above:

I think N80 has already proven the Zeiss scope is the problem. He mounted the scope on a rifle that held zero fine with a Leupold scope, and the same rifle doesn't hold zero with the Zeiss.

This is what I assumed. In truth, the gun has not been fired from a bench rest in at least three years. When my daughter wanted to hunt I put a paper plate out at about 75 yards, shot from the porch and assumed it was still zeroed. Since that time she has killed 5 deer. The last one was at about 30 yards and even though the deer only ran about 15 yards, the shot was very low.

Here is what I'm thinking now: This gun is not accurate. It is accurate enough to shoot an 8" group, which has been accurate enough for the shots that she has taken so far. But it does not hold zero. And there is almost no pattern to where the shots go. And when that is the case, sighting-in gets expensive even with my cheap-o Remington bullets at $1.00 a shot.

So now I do not know what to do with this gun. Pull it out of the stock, remove scope, rings and bases and start over? Sell it? How do you sell a gun that isn't accurate? It is also the gun that both of my kids killed their first deer with. I'm not that sentimental about that sort of thing....just sayin'.

I've got a newer, almost identical Model 7 in 7mm-08 that will be fine for my daughter to use the rest of the season. It is very accurate.

 

[nybirdman]

Well we got it down to the gun any-way.Lots of potential problems.Do a very thorough cleaning,with a copper bore cleaner.Inspect for wear on rifling.I would disassemble and check for loose bedding blocks,hard points ect.If you are not comfortable doing this ,take it to a gunsmith.An eight inch group is not acceptable,something is wrong for sure.