Front and rear dovetails not at same level

[SerenityNetworks]

My 527 Varmint in .204 Ruger was the first of my really accurate rifles and my first CZ.  It was also my first self-mounting of a scope.  In the last year I have learned more about scoping and I'm shooting further distances, so I wanted to rescope the rifle.  I went to setting the rifle level and the first thing I noted was that the dovetails are not at the same level.  I'll be mounting the scope on a one piece DIP dovetail to Picatinny mount, so I may be able to correct this with the mount (but I'm not sure).

I would just never have imagined that the milling would not have had the front and rear dovetail at the same level.  I don't know how much the tops being level matters; that is, if it is critical or if it is more important that the groove yeilds the same level when a mount or rings are attached.  I would just be guessing.   Any expert guidance on how I should proceed will be appreciated.

Thanks in advance,
Andrew

Note:  Each 'picture' is comprised of two photographs pasted/merged together.  (I only have the one surface level.)

[bobanddog]

Do you have some sort of machined surface you can rest the receiver top on and see if there's full contact or not?  It will give you a better idea what's going on than moving a spirit level back and forth.

[SerenityNetworks]

Do you have some sort of machined surface you can rest the receiver top on and see if there's full contact or not?  It will give you a better idea what's going on than moving a spirit level back and forth.

Hmmm.  Good thought.  Hmmm.  The only thing I can think of that would be reasonably close would be a 2' aluminum framed carpenters level that I have.  I'll ignore the level's bubbles, but still take a look at how the surfaces of the level lay on the top of the dovetails.  I'm at a loss to think of anything else I might have around.

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[ZG47]

You need a flat ground piece of steel. The thick part of a machinist's square, 6 inch size or larger, would be fine. A local engineering company could check it very quickly for you.

I would also check your levels either way, on several surfaces, to see how accurate they are. I recently purchased a cheap, short level for noncritical work and tested all six on the shelf before taking one to the counter.

[mauserand9mm]

End of the day, the action may not be completely straight - have seen that before, and it didn't cause any issues. Have also heard of the action sight bases being at different levels - once again didn't seem to cause issues. Everything is built to tolerances and a good design should allow the thing to work within them.

[bobanddog]

True.
Plenty of non-dovetail top receiver guns have been drilled and tapped for scope bases a little bit 'off', and still can be accurate with a scope.  Depending on severity, a scope ring alignment dowel and some lapping, or some offset rings (such as Burris makes) may be required, or nothing at all.  All that really matters is if the scope tube axis is, or can be reasonably made to be, parallel to the bore axis.
Obviously, as the rifle has been accurate with a scope before, this must be the case.

[SerenityNetworks]

I have no idea when I might be able to get to a machine shop to check it out in more detail.  Yet laying the rifle on any reasonably flat surface shows the same defect.  But interestingly enough, when I placed the DIP mount on the rifle the top of the mount was almost perfectly level.  This leads me to believe that the dovetail itself is fine, jus the top of the dovetail is not of uniform thickness.  Once I tightened on the mount (with the left side being slightly tighter) the top of the mount was perfectly level.  Since it's the mount that counts I guess I don't really care that the top of the dovetails are mismatched.

Anyway, the scope is back on and all seems fine.  Now I just need to get out and shoot it.

Thanks,
Andrew

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Feel free to visit my personal fishing, shooting, hunting, and reloading information web site:  http://www.fshrmen.net/