Adjustable mounts: CZ 550 with dodgy geometry

[rustyrotor]

Got a CZ550 at the smith's.
After trying two different sets of rings it seems there is a problem with the bbl/receiver relationship, the result of which is the rifle prints 4" low at 50 yds with the scope elevation adjustment all the way up.

The mounts are not likely the issue, as the bore/reticle relationship is identica with both sets ofmounts. It must be the rifle.

As I am not yet ready to take on the expense of the machine work involved, am looking for a mount solution. I've ordered an adapter from CZ so I can fit Weaver style rings.

This allows me to try the Burris Posi-Align. Unfortunately in 30mm they only offer
+-.10, as opposed to the broad range they offer in 1".

If the scope is at max elevation and is about 4" low at 50yds, does the
+-.10 suffice to get me a 200yd zero? Can someone explain the math?

The only other alternative I've identified that does not entail drilling and tapping are the B-Square 30mm interlock Weaver-sadjustable rings.

But par for the course, B-Square's website explains neither how the rings adjust or how much.

Anybody have them and can fill in the blanks?

Thanks!

 

[rustyrotor]

Really? Nobody at all?

Ok, if you don't like the solutions I've tentatively ID'd, tell me what you'd do if it was your rifle. The gun SHOOTS.

 

[J E Custom]

Got a CZ550 at the smith's.
After trying two different sets of rings it seems there is a problem with the bbl/receiver relationship, the result of which is the rifle prints 4" low at 50 yds with the scope elevation adjustment all the way up.

The mounts are not likely the issue, as the bore/reticle relationship is identica with both sets ofmounts. It must be the rifle.

As I am not yet ready to take on the expense of the machine work involved, am looking for a mount solution. I've ordered an adapter from CZ so I can fit Weaver style rings.

This allows me to try the Burris Posi-Align. Unfortunately in 30mm they only offer
+-.10, as opposed to the broad range they offer in 1".

If the scope is at max elevation and is about 4" low at 50yds, does the
+-.10 suffice to get me a 200yd zero? Can someone explain the math?

The only other alternative I've identified that does not entail drilling and tapping are the B-Square 30mm interlock Weaver-sadjustable rings.

But par for the course, B-Square's website explains neither how the rings adjust or how much.

Anybody have them and can fill in the blanks?

Thanks!

I don't know a lot about CZs but any rifle can have problems so hear is what I think.

First the barrel to action fit should be in line (Very hard to do otherwise).

I have seen the mounting screw holes drilled off the center line but this produces left or right
problems with the scope/sights, so I would have to rule out this problem.

The same goes for dove tailed receivers.

Next would be the bases or rings If the rings are Identical from the mating surface to the
bottom of the ring this can be eliminated,

My guess would be that the bases are not the right ones and cant the scope or you have a scope problem. The bases are the odds on favorite for this kind of problem. I have had some
problems with even the best bases and rings.

I have seen lots of bases that were ether machined wrong or labelled wrong That's is why
most actions have two different spacings on the sight bases so they cannot be installed
backwards because of the different height requirements.

Just my opinion

J E CUSTOM

 

[caliber]

I just bought a 22LR CZ 453 varmint, and had the same problem. I had Millet high rings on it and had about 3/8" from the top of the barrel to the bottom of the objective lense. Put on a set of mediums and it dropped to a 1/4". Never would have thought an 1/8" would make a difference,but it solved my problem. How high is your scope from the barrel?

 

[rustyrotor]

Just about 1/8"