Scope zero shift

Ben10

Member
Apr 1, 2015
246
13
Am I the only one that every other time I come to my gun the zero has shifted slightly? 

It never used to do this but lately it has got worse. It's slowly creeping down in POI, It seemed to move a whole MOA in one jump and has done this twice now and is still slowly creeping down. 

I have checked the fps and it is exactly the same as before, all screws and bolts are tight. 

I am trying to work out if it's something I can prevent or not.

ETA - it's a .22 bobcat with Hawke sidewinder. Installed by the shop. 
 
Wow, I was getting ready to make a similar statement. Since, I have got my shroud back from Neil. I have had a hell of a time with finding a zero when the shroud is on vs when it is off. I have two POI's. It's completely crazy. I haven't changed anything on the rifle at all every thing was exactly the way it was before I sent my shroud to him. So I feel your pain on this one. I have spent the last couple of weeks checking every thing so. I am just going to do more experimenting and see what happens. Best Steve 
 
Ben

Like others have said; I would check your turrets. Make sure the allen screw is snug as well (the one that lets you zero out the turret). I think the best suggestion is to try a different scope to confirm whether it the rifle or the scope.

Also you may want to check the shroud. I have found that different shrouds sometimes give me a different POI. Always consistent, always different, no signs of clipping with either. It could be how the air is influencing the pellet just before it leaves the shroud. AoA put out a video in this thread on how to remove the shroud http://airgunnation.dev/topic/how-to-remove-the-barrel-shroud-on-an-fx-bobcat/?view=all


 
"Am I the only one that every other time I come to my gun the zero has shifted slightly?"

A normal problem with budget scopes.

Is your focussing correct? Does the crosshair move against the target when you move your eye around?
Try turning turrets all the way, up and down, left and right, ten times. Then make sure that the crosshairs are centred, both in turret turns and optically. Repeatedly tap scope with hand. Again check optically centred. Without moving turrets from centre position, shoot some groups to test consistency of scope.

If you have to move turrets a lot in order to zero, and it still doesn't hold zero, then I would suggest the problem may be that the quality of manufacture isn't the best and that you should consider either a warranty claim or adjustable rings to attempt utilisation of efficiency of the centre of most scopes.
 
Each pair of my spectacles, with good anti-reflective this and that lenses, cost £250 (ish) and a scope's lenses are more complicated; even before we start on the manufacture of the rest of each scope. A scope costing a customer £300 will likely have cost the store/retailer £150 tops and its manufacturing cost is likely to be ££50-£70 ($70-$110) tops. Even with lower Chinese work costs, the material and power costs being comparable to say the USA, there isn't the money in a $70/$100 scope to go high quality.

$4,000 dollar scopes, manufactured and designed to the highest standards etc, still have their "issues". In my opinion, most all scopes under say $1,500 are "budget". Hawke (inc Sidewinder) scopes are what I would class as budget, they have their "issues", certainly aren't "tactical" (that cheap marketing term is one of the most overused in gun culture) in any professional sense. Backed up by the Chairgun software, and some set-up work by the user, a Hawke scope can obviously be quite a flexible and good tool for an airgunner. Unfortunately, buying a scope is very difficult for any consumer, as brands/manufacturers aren't usually honest and certainly won't tell you if a particular batch of scopes has an extraordinarily higher degree of certain problems or whether the lenses weren't of their normal high standard. 

But, if you have got turret tracking accuracy problems, I would claim on the warranty.
 
I may get shot for doing this, and this is last years prices but as an example for the UK:

Hawke Sport HD 3-9x40 IR SRP £79.95; Net of VAT/Sales tax £66.63; cost to retailer £38.95; gross profit £27.68; gross margin 41.5%.

With a scope costing £38.95 to the store, and discounting Deben's element, it is actually quite an amazing feat that a scope that will happily meet the needs of 90% of airgunners is probably made for ...... est.....£15/$25.

 
Thanks for the examples cookie. I can see what you mean regarding budget. 

Wgen you you say a turret tracking issue, are you referring to the zero shifting on its own? I ask because with regards to being able to move the turrets, say to change from a 50 yard zero to 100 and back and forth between, it tracks back to the same place each time... It seems that it is shifting when it's not being used. 
 
Zero shifting on its own is commonly down to the turret tracking mechanism being due to poor build/design, which is classed as a “issue” in the majority of budget scopes but a “fault” in a $4,000 scope, though such a problem can also be down to an internal fault such as the reticle becoming loose.

But, please do the tests originally proposed. Many people incorrectly think their scopes are faulty, when in fact they don’t understand the “issues” with that scope. Moving crosshairs may be due to the shooter having incorrect eye piece or objective lens focus. Use manufacturer marks on the objective focussing/parallax wheel as just a guide. Better to make your own focussing markings.

Even though the “tactical” part of Hawke’s sidewinders design/advertising isn’t valid, I would be astonished if they refused to honour the warranty of a scope that they themselves claim is “tactical”… because I would say that working (100% of the time) tracking to at least 50% of turret movement is fundamental basis for a scope being claimed as tactical. I think you are correct to expect such performance from such an advertised scope. if you return it, don't send the mounts, as they will likely check it and then send out a new scope.
 
I unfortunately haven't had any shooting time since I started his thread so haven't managed to fit the checks yet that cookie mentioned. But I have had a thought... Would removing the action from the stock have any effect on the zero of the gun?

I would hazard a guess it could/ would seeing as especially on the bobcat, with the air cylinder screw torquing against the cylinder it could have a "different" pressure against the action??