Scope zeroing issues - is my receiver drilled wrong or barrel misaligned?

bush1 said:
Agreed, a very small amount of screw hole offset makes a much bigger offset at 100 yards. In sailing we use the 1 in 60 rule. Steering 1degree off course will put one 1 mile off course at 60 miles. Same idea with base tap holes misaligned.
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If holes are 4" (circa 10 cm) apart on receiver, and mis-aligned 0.001" (computer paper normally 0.004" thick), then that will be 0.9" (circa 2.3 cm) mis-aligned at 100 yards. But to get the error that OP is describing, something is "dozens" of 0.001" out of line, to be that far off at 100 yards / meters ...
 
Suther said:
Oh i think it's pretty clear at this point....
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Your writing in the rest of the post (#57) is much more clear than the OP. No offense to the OP - Suther is paraphrasing, so that's bound to happen.

If the OP agrees that you are paraphrasing correctly, I can't disagree with your conclusion.
 
I don’t know if it’s only the angle in which the picture is taken, but that rear post on the base seem very high, much more than 20 MOA.
The angle of the scope relative to action - look the scope bell is diving - seem very odd.
 
Is a good point Janeau makes in Post #63 - a 20 MOA rail causes the rear ring centre to be higher by 0.022" than the front ring centre - if the rings are 4" apart - 0.028" higher if rings are 5" apart - OP did not clarify in the original post - is that 20 MOA base made for that rifle? For example, a 20 MOA base (front to back ring centres) is likely different heights on a Model 70 Winchester, than a 20 MOA base for a Mauser 98 and different again to a Mauser 96? OP would lose a lot of, or most of, his windage adjustment in that scope, if he is close to maxed out with the elevation turret.
 
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OP - looking at the pictures you have in Post #1, and reading your words there - return to mechanical centre - get the left / right set correctly - I would do that by shooting - sounds as if you trust that laser dot to be pointing where the bullets will go? By getting your reticle "zero'd" for left and right - now you will have maximum available for up / down - that your scope can give you, in that set-up. Or vice versa - get your elevation where you want it - then you will have the most left / right that the scope can give. Do not try to do both at the same time. If you have that scope mounted square, groups should track up /down or left / right to be parallel with the "legs" on your reticle.
 
^^ Have you checked the laser in another rifle ?? The one I have can be slightly off at shorter distances. As potashminer said, a few thous can make a big diff at distance. I only Z at ca 20 yds and that gets me within a few inches, at least onto paper. A lot depends on how well the collet fits the bore.
 
Anyway I think I have conclusive enough evidence to say it's a combination of mount and scope issues. I took another scope, returned to 0 by counting clicks, put on another mount and rings, and it was dead center by laser and bore sight without any adjustments at all
 
I had similar issues with a scope, so I thought. It ended up being the rings. You have to eliminate everything first even if you think it is not the problem. I ordered the Diamondback Tactical 3-9 at cabelas and received it today. On sale for $249. What a difference to the crossfire I have on another gun. I am glad I didn't jump on the Tenda sale for the Bushnell Nitro last week. Using Nikon 2 piece cantilever mount with 0 MOA on my BCL Bison. Almost dead on right out of the box.
 
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machohugeaxe said:
Anyway I think I have conclusive enough evidence to say it's a combination of mount and scope issues. I took another scope, returned to 0 by counting clicks, put on another mount and rings, and it was dead center by laser and bore sight without any adjustments at all
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And there we have it.

Thanks for reporting back OP.
 
alpining said:
And there we have it.

Thanks for reporting back OP.
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I guess its not always rainbows and butterflies purchasing second hand. My first time purchasing something that had issues on EE! At least I don't think it was me, I always torque to 16 ish on rings

Update from Vortex:

Fault Found:

Scope tube severely crushed at both end ring points
Tube bent towards objective bell



Service Notes/Comments:

Scope tube crushed due to overtightened rings. This has caused the issues experienced by the user.
*Please ensure quality rings are torqued to scope to 15-18 inch lbs. using a properly calibrated torque wrench, no Threadlocker on tube screws*
 
fritzhanzel said:
^ Thanks for getting back, happens more than you think. Especially when some experts on CGN recommend 65 inch lbs.
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I watched a guy at the range torquing down his rings with a screwdriver and he was reaving on it.
Had to be at least 100 inch pounds … lol

I was gonna tell him that he shouldn’t torque them to tight but I could tell he was one of those thick skulls.
 
45C said:
I watched a guy at the range torquing down his rings with a screwdriver and he was reaving on it.
Had to be at least 100 inch pounds … lol

I was gonna tell him that he shouldn’t torque them to tight but I could tell he was one of those thick skulls.
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When I hand tighten until I feel a bit more resistance, I know I am at around 20 inch pounds. Not sure if you can hand tighten to 100 inch pounds, depends on the weight of the screwdriver I guess. Better use a 1/2 inch wrench to be sure it is tight :cool:.
 
Right on, glad that part worked out for you. That sort of thing does add value to Vortex products on the used market, compared to some other brands.
 
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