CZ 550 Scope Mounting vertical problems

[benchracer]

I have a CZ550 Safari Magnum that I have recently mounted a Zeiss Conquest 4.5-14x44 AO scope on using Warne Quick Detach Rings. The CZ 550 uses a 19mm dovetail as the mounting surface for the rings.

When zeroing the rifle @ 100 yards, I am running out of up travel WAY before I can get to a 100 yard dead-on POI. According to my calculations, it would take about 16 MOA to reach my 100 yard POI and another 15-20 MOA to get me back to being somewhere near the center of the scope's vertical adjustment range.

Where should I be looking to find the source of misalignment? I would think that the integral dovetail would be visibly mis-machined in order for it to be off by 30+ MOA or so. Ditto the scope rings. I have considered having the action drilled and tapped for a picatinny rail, but I am not sure if that would solve the alignment problem and I don't want the scope mounted any higher above the bore.

Is this something a competent smith can easily find and correct?

 

[threejones]

I'm sure you've already tried this, but I'll throw it out there anyway. Have you tried swapping the rings front to back. I had a set of rings that were noticeably different heights. It was a pain at first, but once I figured it out it saved me buying a 20 MOA pic rail (sorta)

 

[FEENIX]

I don't want to assume anything but are the rings the same height? For instance, Ruger M77 MKIIs have two different size ring heights; you put them backwards you'll have similar problem you're describing.

Just a thought for your consideration.

 

[FEENIX]

I'm sure you've already tried this, but I'll throw it out there anyway. Have you tried swapping the rings front to back. I had a set of rings that were noticeably different heights. It was a pain at first, but once I figured it out it saved me buying a 20 MOA pic rail (sorta)

OOPS, you beat me to it as I was typing my response.

 

[benchracer]

On a CZ550, the rear ring has a "recoil lug" that engages a slot in the receiver. The front ring has no lug. It is not possible to reverse the two. I suppose it is possible that the front and rear rings are mismatched in height, but I would think that the misalignment would be pretty obvious when trying to tighten the ring halves together.

 

[bruce_ventura]

I had a similar problem when installing a scope on that model CZ rifle chambered in .375 H&H. After optically zeroing the rifle, the impacts were about 20" low at 100 yds, hitting dirt in front of the target. It was difficult to even see the impacts because there was so much dust kicked up. I was using CZ rings. Luckily for the customer, the scope had barely enough adjustment get to a 100 yd zero.

I concluded the problem was barrel vibration. The stock was solid and the impacts were in similar locations for two different shooters. I'll bet your rifle has the same issue.

I would normally recommend that you use Burris Signature rings with offset inserts, but I don't think they are available for the CZ long action. Next, I recommend that you change ammunition. Barrel vibration of this magnitude will vary a lot between different loads. Failing that, you could bed the scope in the rings to add about 20 MOA of elevation. See YouTube videos on this subject. Place a 0.032" spacer in the bottom of the rear ring and embed it in bedding material.

 

[benchracer]

I had a similar problem when installing a scope on that model CZ rifle chambered in .375 H&H. After optically zeroing the rifle, the impacts were about 20" low at 100 yds, hitting dirt in front of the target. It was difficult to even see the impacts because there was so much dust kicked up. I was using CZ rings. Luckily for the customer, the scope had barely enough adjustment get to a 100 yd zero.

I concluded the problem was barrel vibration. The stock was solid and the impacts were in similar locations for two different shooters. I'll bet your rifle has the same issue.

I would normally recommend that you use Burris Signature rings with offset inserts, but I don't think they are available for the CZ long action. Next, I recommend that you change ammunition. Barrel vibration of this magnitude will vary a lot between different loads. Failing that, you could bed the scope in the rings to add about 20 MOA of elevation. See YouTube videos on this subject. Place a 0.032" spacer in the bottom of the rear ring and embed it in bedding material.

The point of impact issue is occurring during load development, so I am not sure changing ammunition is the answer. However, bedding the scope in the rings sounds like that would be a viable fix. If that solution were employed, I am guessing that the rings would need to be lapped and that bedding of the front and rear ring would be required to accommodate the new angle of the scope tube. Is that right?

I will probably consult a good smith to do the work, but now I at least can hold an intelligent conversation regarding the fix for the problem. Thank you for your insight.

 

[bruce_ventura]

I think lapping would take too much time. I would bed both the front and rear rings.

 

[benchracer]

I had expected that lapping would have to be done to allow for the change in vertical cant of the scope tube. If simply bedding the front and rear rings would do the trick, so much the better...

 

[FEENIX]

It's old (not sure what the OP's final fix) but found this FYSA ...

from sucngas
wrote 4 years 44 weeks ago
I bought a cz550 in 416 Rigby last year. The action is perfect. The trigger is amazing. It shot dead on with the iron sights. The only problem I had was that when I mounted the scope, it shot way too low. I adjusted the scope as far as possible, still not enough. I contacted the company, and was told that they never really intended for the big bores to be used with a scope (why the mounts then????), but they offered to replace it no questions asked. I hated to do that because I had already had the action glass bedded. I honestly think that the problem is with the rings (also cz, but they don't measure the same height), not the action. I'm going to try a different set of rings and see if that fixes it, but for now, I just put a .020 shim under the back ring. Works great. It will shoot under 3/4" at 100 yards with both Norma and Hornady ammo. As a matter of fact, I used it to shoot a five point bull elk last year. Poor bugger never knew what hit him.

(CZ 550 American Safari Magnum | Outdoor Life)

Good luck!

 

[benchracer]

VERY useful thread and a good find. Thank you!

 

[bruce_ventura]

Every time I've seen someone try to correct an elevation problem using a shim underneath the scope tube, the results were bad for the scope. The shim reduces the contact are between the ring saddle and scope tube. Tightening the ring screws puts dents in the scope tube. Because the contact area is low, the scope slips in the rings when the gun is fired, causing gouges in the tube.

Shims alone are not a good approach for a magnum rifle. Bedding the scope tube with a spacer in the bedding material works just fine.

 

[Dr. Mac]

I'm late to the thread but I had the exact same problem with a CZ 550 in 9.3x62 using any 3x9 or higher magnification scope; 1 inch or 30mm main tube diameter. Not so with a 30mm 1x8 with more up elevation adjustment or with my CZ 6.5x55 with any scope. I have concluded that it is a design flaw in the 19mm dovetail system with heavy bullets and standard scopes that CZ should correct on these otherwise strong and affordable rifles. My solution was to use an aluminum clamp on 20 MOA Picatinny rail which solved the elevation problem completely with any of my scopes but did raise the scope height about 0.375" from where it would have been. I like the rifle a lot and considered having a gunsmith mill the dovetails off and installing one of the excellent Ken Farrell steel picatinny rails made for the 550. Milling the dovetails off would also solve the scope height problem if you can't live with it. So far I can. Great post.

 

[dwightb]

I had the problem only worse with my CZ 550, talking 60 MOA. A lot of CZs shot low to bore sight. Sent it to Tripleriver gunsmithing. They wont tell anyone what they do but mine is good now, $100 plus shipping both ways. EGW makes a +20 MOA rail for the CZ, the rail just makes the scope high.