Possible Nikon BDC problem

280fan

280fan

New member
I've never seriously blamed optics for grouping problems at the range, but I'm beginning to think I've finally bought a defective scope. I'm curious if anyone else has run into this.

The rifle is a Ruger #1 270 WBY. The scope is a 4 x 16 x 44 Nikon BDC, bought brand new. The rings have been lapped, I lap all my rings personally. The scope has been removed once, rings lapped some more and remounted, all screws torqued.

The problem is, no matter what ammo I shoot, handloads or WBY factory, at 100 yds the rifle will shoot 2 or 3 rounds into a MOA group, then for no apparent reason shoot the next 2 or 3 into another MOA group centered about 2.5 inches low and left, then turn around and shoot the next few back into the original group. Just keeps alternating back and forth between 2 groups, about 2.5 inches apart.

Barrel heating is not a factor, doesn't matter if I wait 3 min between shots, or 10 min, or 20 min, still does the same thing.

I'm shooting off a bench, using a Sinclair front rest and Protector rear bag, everything good and solid. It's too much coincidence to think bad shooting is producing two separate MOA groups, repeatedly.

Originally I had a Leupy 4.5 x 14 mounted on this rifle and it shot fine. I took the Leupy off and mounted it on a 25-06 and put the Wby in my safe. Now, 2 years later it's shooting double groups with a Nikon.

Anyone think of any possibilities other than the scope?
 
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Sure sounds like the scope reticle is jumping on you...especially since another scope produces expected results on the same rifle..
 
Yeah, that's what I'm thinking, just wondering if anyone had another possible explanation before I call Nikon.

I'm confident they'll stand behind it.
 
Couple questions:

Which Nikon scope?

Did you use the same rings on both scopes?

Reason I asked is because I had a Monarch that did this and it was because of the rings.

My son-in-law put a prostaff on his 30-06 and it did the same thing too.


Nikon will take care of the problem or at least they have for me in the past.
 
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It's a Monarch. I'm at work and can't look at it, but I know it's a Monarch, don't remember if there's a further designation, but I know I paid about $450 for it. I know, I sound like a dumba**, but I'm not all that familiar with Nikons, all my other scopes are Leupys, or old original Redfields.

I used the same rings. It's a Ruger and they come with rings. I own 4 of the #1s and have never had any problems getting good secure scope mounts using the Ruger rings.

As I said earlier, the rings are lapped. I always lap my new rings, and every time I change scopes I relap. I'm confident the scope isn't physically moving in the rings.

Like most all of us, I've had accuracy issues in the past and have, at times, suspected the scope. I've always figured out the problem though and it's never turned out to be the glass. This time I believe the scope is actually going to be the culprit though.

Thanks for the input.
 
Is it possible to lap the rings too many times so that they are now a little bigger than the diameter of the scope, thus allowing movement?

Curious to know?
 
Yes- It can cause all kinds of problems such as slipping, weaken the rings, etc.

I lap and I have over lapped which caused the above problems.

With a lot of today’s rings like aluminum, adjustable, etc it's not necessary to lap, but I still check alignment because even the precision that goes into making some of these rings still could leave uneven surfaces from burrs, coatings, etc.

On some rifles, I’ve had to bed the mount, shorten the screws for the mount(bottomed out), etc because of the contour of the mount and/or barrel.
 


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