Massive POI shift on shot one after mounting scope

[Donkey]

Hi folks.

I use a Weaver T-36 when doing load development on my Palma rifle.

I consistently get the first shot after mounting the scope 2.5 MOA at 12 O'clock. All following shots revert to the previously dialled in elevation.

I am using "Warne Rings Maxima QD 25mm" scope rings which are a bit tricky to set up as they are vertically split but I did my best.
I have an alloy picatinny rail beaded to my action.

Has anyone seen this before?

 

[treeman]

is that a freshly cleaned barrel or a cold fouled barrel? The cold bore shot from a clean barrel will typically be farther from the group than from a fouled barrel.

 

[CatShooter]

Hi folks.

I use a Weaver T-36 when doing load development on my Palma rifle.

I consistently get the first shot after mounting the scope 2.5 MOA at 12 O'clock. All following shots revert to the previously dialled in elevation.

I am using "Warne Rings Maxima QD 25mm" scope rings which are a bit tricky to set up as they are vertically split but I did my best.
I have an alloy picatinny rail beaded to my action.

Has anyone seen this before?

Some scope mounts do not go back to "0" when remounted and need a shot/recoil, to settle them.

 

[Donkey]

is that a freshly cleaned barrel or a cold fouled barrel? The cold bore shot from a clean barrel will typically be farther from the group than from a fouled barrel.

This only occurs with the scope. With the open sites cold bore shots are within 0.5 MOA.

Some scope mounts do not go back to "0" when remounted and need a shot/recoil, to settle them.

Thanks CatShooter.
- Should I be concerned about this when looking for the high levels of elevation accuracy required for load development?
- Do we know what causes the rings to have 2.5 MOA in their locking mechanics?
- Is it possible to rectify this with my existing ring design? Is the inability to use a bore bar the limitation in the rings design here?
- If not what rings and ring mounting technique would be recommended for this application where I need to unmount and remount the scope regularly?

 

[CatShooter]

Some scope mounts do not go back to "0" when remounted and need a shot/recoil, to settle them.

Thanks CatShooter.
- Should I be concerned about this when looking for the high levels of elevation accuracy required for load development?
- Do we know what causes the rings to have 2.5 MOA in their locking mechanics?
- Is it possible to rectify this with my existing ring design? Is the inability to use a bore bar the limitation in the rings design here?
- If not what rings and ring mounting technique would be recommended for this application where I need to unmount and remount the scope regularly?

Mounting scopes is a very opinionated issue. I have been through them all (or most of them).

Other than external mounts for Unertls and Targetspots, my current set-up is either Leupold or Warne, two piece cross slot bases, and Burris Signature ZEE rings.

I set the scope up so the 100 yd "0" has the elevation turret almost at the bottom of it's adjustments (so I get all of the "up" I can).

They are not "quick detach" with levers, but the scope comes off in two minutes with a screw driver.

It is repeatable, solid, and I love having all the elevation available to me (I at shoot far things).

Also, with any detachable mount - when you return the scope/rings to the rifle's base, push it FORWARD hard, before locking it up with the screws or levers - if you don't the rifle will shift the scope on the first and second shots until it is forwards.

<edit> I DON'T use the kind of rings you have pictured - they look cool, they work suckie.

 

[BoydAllen]

Just out of curiosity, did you lap the rings? I imagine that that would not be nearly as easy with vertically split rings. To me those rings seem like a triumph of looks over function. I always choose horizontally split rings made from aluminum, since they are plenty strong, and much faster to lap in. For applications where there is the budget, and Picatinny bases are used, I think that Seekins makes some very fine rings. Even on an one piece, or integral base, I have seen evidence, as I lapped, that doing so was a good idea. If you do lap some rings, take your time and do a thorough job of getting all of the grit off of the inside of the rings. For this, I find that light oil followed by some kind of solvent works best, the oil floats the grit off of the surface better.

 

[Donkey]

Thanks folks.

Yes lapping does seem hard to do with the vertical split rings.

I do push them forward when I mount up. I wonder if one is hitting before the other.

There must be a way to set these vertical split rings up properly... Anyone had good results or am I just best to throw them away and get some of these. http://www.seekinsprecision.com/parts-and-accessories/scope-rings/1-tube-76-4-cap-screw.html

How is the height of scope rings measured BTW?

 

[BoydAllen]

Sell them with an ad on this site. They are free. Recently I have gotten rid of a couple of hundred dollars worth of odds and ends that way. If I remember correctly, ring height is from the top of the base (base thickness varies but should be specified somewhere.) to the center of the scope tube.
http://www.cheaperthandirt.com/MediaPages/ArticleDetail.aspx?mediaid=922

 

[seymour fish]

Mounting scopes is a very opinionated issue. I have been through them all (or most of them).

Other than external mounts for Unertls and Targetspots, my current set-up is either Leupold or Warne, two piece cross slot bases, and Burris Signature ZEE rings.

I set the scope up so the 100 yd "0" has the elevation turret almost at the bottom of it's adjustments (so I get all of the "up" I can).

They are not "quick detach" with levers, but the scope comes off in two minutes with a screw driver.

It is repeatable, solid, and I love having all the elevation available to me (I at shoot far things).

Also, with any detachable mount - when you return the scope/rings to the rifle's base, push it FORWARD hard, before locking it up with the screws or levers - if you don't the rifle will shift the scope on the first and second shots until it is forwards.

<edit> I DON'T use the kind of rings you have pictured - they look cool, they work suckie.

Push forward. Absolutely

 

[seymour fish]

Hi folks.

I use a Weaver T-36 when doing load development on my Palma rifle.

I consistently get the first shot after mounting the scope 2.5 MOA at 12 O'clock. All following shots revert to the previously dialled in elevation.

I am using "Warne Rings Maxima QD 25mm" scope rings which are a bit tricky to set up as they are vertically split but I did my best.
I have an alloy picatinny rail beaded to my action.

Has anyone seen this before?

Although these rings are a PITA, it is possible to get good service from them. Something is moving . if rings are properly torqued in 3 stages, both with solid crossbar contact pushed forward, and holding zero after the first shot, would begin to wonder if the scope reticule needs a shot to settle

 

[Willie]

One way to check this out is to loosen rings and levers to where scope is free. Pull front ring forward and lock down against cross bar. Repeat on rear ring. Torque to specs, if you can with lever setup??? Align scope and torque to specs.

I don't use this type ring, but I suspect only one ring is hard against crossbar, as seymour fish mentioned, and the first shot is causing a slight, but consistent movement. That or one lever's torque is bearing more of the initial shot. JMO

 

[MQ1]

Hi folks.

I use a Weaver T-36 when doing load development on my Palma rifle.

I consistently get the first shot after mounting the scope 2.5 MOA at 12 O'clock. All following shots revert to the previously dialled in elevation.

I am using "Warne Rings Maxima QD 25mm" scope rings which are a bit tricky to set up as they are vertically split but I did my best.
I have an alloy picatinny rail beaded to my action.

Has anyone seen this before?

I use the Warns only on rifles where the scope is not expected to be removed, and I never found the Quick Detach to operate in a return to zero fashion...the one QD pair I owned I sold for that very reason. The non-QD versions have worked better for me, but I really don't think the design lends itself to returning to zero once removed.

They are a real bear to lap, but have worked well on my hunting rifles where a solid snag free tough mount is the ticket.

Maybe your base and the QD mounts don't quite settle in until you fire a shot. Does the base and the mounts seem to mate well?

MQ1

 

[JRS]

This thread is more than 3 years old

 

[MQ1]

This thread is more than 3 years old

This reminds me of the saying:

"Some people find fault like there is a reward for it." -Zig Ziglar