Bought a Geissele High Power National Match extended mount and a Vortex Viper PST 1-4 for NRA High Power matches.  The optic has to sit well to the rear for what I perceive to be proper sight picture and eye relief in prone.  I am thinking I might want to try their non extended High Power mount but only because of how it sits in the mount.  Anyone have a similar setup for High Power?

Just move the mount back a little on the rifle.

Yeah, I thought about that, I just placed the mount as far forward on the upper as I could out of habit.  I guess I could move it to the rear a couple of notches and re-mount the optic.  But then my OCD would kick in.

I shoot a very aggressive NTCH and ended up with the mount 2 slots back to center the scope turrets between the rings.

It’s still far enough forward that I don’t think a regular canti mount would work and I’m not in a position to buy a bunch and test.

It all comes down to required eye relief, nose size and how you mount the rifle.

From your photos it looks like my eyepiece (Burris) is about 1/4” further forward than yours.

It may depend upon which buttstock you're using.  With the A2 stock, I had the scope mount and the scope all the way forward for optimal position in prone, slung up.  I've notice folks who shoot prone with bipod definitely do not need or have to have the scope as far forward.  More like where I would be for standing offhand.  If you use an adjustable stock, then find your optimal stock setting (for prone) and then adjust the scope location from there.

To each his own I guess.  My nose is up by the charging handle.  This ensures consistant head placement and acts like a kisser button on a bow. To get the 3 inches of eye relief the scope needs to be up near the case deflector.  But if it works for you, back it up.

I shoot the same optic in SR. Mine is mounted 3/4”-1” farther forward FWIW.
For reference, the rear edge of my magnification ring is directly above the dust-cover detent.

@USMC88-93

A little late to reply, but I used that scope before switching to Nightforce and I had issues with the mount rings that close to the turret.  You should try to center it between the rings, if you can (like below).  If you can't center it, run a box test to ensure you're not binding the internals.

I tried to avoid scrutiny here in CA for the possibility of shooting somewhere in public and having some law enforcement challenge the “featureless” issues, so I am running a regular A2 stock. No chances of being challenged on it being adjustable...

That said, I learned through several XTC and MidRange matches, that it took me a while to settle on scope position.

I have a Vortex on one rig that is a little farther forward than yours, and I’m nose to charge handle in prone.

I suggest you spend a serious effort to establish a good position in all three, Offhand, Sitting, and Prone, then move the mount rings to a better spot when you are sure where the scope needs to be. Hopefully, it won’t require anything strange enough to cause functionality issues with the turrets.

The Box Test was good advice. I had one NF and one HiLux that hung up on their first moves. They have both run smoothly since and I run the turrets up and down before starting any sessions now just to be sure.

BTW, I have been very impressed with the boresight repeatability of the Gisselle mount. It has been within less than 150 microradians (1/2 MOA) on a dozen remove-replace cycles.

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