Some of you may remember a post that I made last May regarding a CZ 550 American Safari in .416 Rigby that could not be made to shoot to point of aim at any reasonable range. The rifle printed Norma factory 400 grain solids 6" low at 25 yards with Leupold 1.75X6 at max elevation. The rifle was returned to CZ and they replaced it with a different barreled action and the explanation "rifle would not bore sight".
The replacement rifle exhibited the same tendency. 5" low at 25 yards, max scope elevation. Thinking that the odds of getting two defective barreled actions with exactly the same problem should be very remote, I proceeded to send scope back to Leupold. They assured me all is well with the scope.
Dave Talley and Gene Turner at Talley Manufacturing sent me a free replacement set of QD rings and did not think their product was the problem. Sure enough, the replacement rings shot exactly like the first set on the replacement rifle.
I again returned the rifle, scope and mounts to CZ. Friday, I talked again with Mike Eagleshield, CZ's senior USA gunsmith. He allowed that he was able to get the rifle to shoot dead on at 100 yards with the scope set at mid elevation adjustment. He accomplished this by super glueing shim stock to the bottom of the rear Talley mount. In effect lowering scope reticle to rifle point of impact. Hopefully, I will receive the weapon next week and test fire to confirm Eagleshields comment.
My question is does anyone else have any experience with a repair of this nature? Should I feel comfortable hunting dangerous game with this weapon? Is it wrong for me to feel cheated that a new weapon has to be repaired in such a manner?

Jeff

Sort of. I placed the shims directly under the scope tube in the ring. Two methods to achieve the same ends. Either the receiver bridges are not the correct height, the rings are not correct height, or a combination of the two.

ASS_CLOWN

As long as the shim makes full contact between the base and receiver and is fully "captive" it should be fine. Were the rings lapped in before the scope was installed? That can be important for alignment. As to ASS CLOWN'S placing the shims in the scope ring itself, that's the worst place to put them, makes it really easy to screw up a good scope doing it that way. Also, as long you have the correctly matched ring set, ring height has nothing to do with it.

Doesn't the shim under one base result in a "bind" on the scope in a vertical direction, much the same as the "bind" in the horizontal from the scope rings not properly aligned?

Or is the amount of the shim so small as to be inconsequential?

Over shimming will result in binding.

Craigster,
As far as I know the ring sets were matched as both sets performemed exactly the same. The rings were not lapped prior to scope mounting. Could this account for the huge difference in point of impact?
One thing I did not mention is that the second rifle shot dead on at 50 yards with the factory iron sights. As both sights are mounted on the barrel, I suppose they could be adjusted to coincide with the point of impact. I did not test the original weapon with the iron sights.
CZ did say on the first replacement that they have had some problems with barrel/action alignment on the large caliber weapons. I still feel like that is the root of the problem.
Would rebarreling this action yield the same results?

Thanks for all the input as I am confused as to what to do.

Jeff

craigster,

Thanks for setting me straight! You are well aware that I have never had a gun let alone a scope!

ASS_CLOWN

jeffrey,
I don't think unlapped rings would result in that great of difference in POI. Iron sights have quite a bit of leeway, so that would account for dead on @ 50yds with them. My take is that the barrel and action are not in a straight line. If the receiver threads are miscut rebarreling wouldn't help, the POI could wind up any where in a 360 degree circle. If the barrel threads are miscut rebarreling might help. I went thru this not too long ago on a used M70 Win. I never figured out whether it was the barrel or the receiver (or both). I shimmed the bases and all is well. Bummer that it's a brand new rifle, but my M70 was new to someone at one time also. Some of the stuff comin' out of rifle factories these days can be real disappointing.

Jeff - If you are going to keep the rifle and aren't comfy with shimming the scope base, you should consider custom-made bases. Mark Stratton, for one, can machine bases for your Talley rings that will absolutely put your scope in the proper position to zero with minimum reticle adjustments. And they will look worlds better than any off-the-shelf bases.

If you move the reticule too far off centre, you are then using the edge of the lens system. Where the aberrations in the glass are worst.

Glen71 has the best solution.

Burris Signature rings will allow you to change inserts until approximate converge.

HEY GUYS,

Thanks for all the replies. I plan on keeping the rifle as I hope to return to Africa some day. I was not aware of Mark Scrantons service and don't understand how he machines bases as these are already machined into the action. Anyone have a link to his services? Should I have to put up with this in a new rifle? What if I want to change the scope or mounts? How much stress is being put on the scope? In nearly thirty- five years of shooting, I have never had this problem.
Thanks for the replys.

Jeff

Yes, I have made similar "repairs" myself with rifles mounting high-magnification scopes that had insufficient internal adjustments so shims had to be used under the rear mount ring to make the scope point down more in relation to the line of the bore. This is a common problem, and shimming is the common fix. I used slices off of aluminum beer cans, and did not glue them to the ring and had no problems later, but I guess the glue job would make the fix even more secure.



I think this fix is quite acceptable. Just make a small mark on your scope tube with a sharp pencil at the front edge of the rear scope ring so you can be sure that the scope doesn't slip under recoil when you zero it. If it stays in place for 20 rounds or so, you can feel some confidence that it will be where it should be when you see Mr. M'Bogo through it!! As to whether this placement of the shim will put unacceptable torque on the scope tube, I suppose this is a valid consideration. It will of course depend on hgow thick the shim is, and also on how well aligned the rings are to begin with. It takes VERY LITTLE shim thickness to move the POI a pretty large amount! I dounbt that placing a shim under the rear base is going to put less strain on the scope tube, (if any) than shimming the rear ring, because the amouint of correct required will be the same regardless of where the shim is placed. I have never experienced any adverse effects on a scope from use of shims in the mount, but the heaviest-recoilling rifle I have used shims on was a .375 H&H, and of course there's more stress created by the .416 Rigby!



Good luck.

Jeffery -

Will it work? Yes, I have a shim under the base on a T/C Encore 209x50 that has stood up to a few years of max loads.

Is it acceptable? That is entirely up to you. I felt cheated on my gun, it was new, I paid hard earned cash for it and as far as I'm concerned it has a defect. I was in a rush to take it to NM on a hunt so I didn't return it. The problem you are having sounds like it is occuring on many of their large caliber guns. They have a problem that they need to address and it appears as if they know it. It is up to them to make sure that you are satisfied. If the shims are what it takes, then enjoy.

Ken

This might be stating the obvious but why not try a set of CZ rings? If they don't work you can return them.

I have a 550 in .416 and have no problem with the CZ rings.

Hey guys and thanks for the responses. The saga continues today when I received my rifle back from CZ-USA. I immediatedly opened and inspected the package. It was obvious to see the shim under the rear mount. Not blued and poorly fit. I mounted the scope and indeed it seemed to fit the rifle OK. When I dismounted the scope, I heard the shim immediately fall to the floor. Under field conditions, it would probably been lost. Since it was out any way, I measured the thickness of the shim. It was +/- .0020.
After measuring, I called Eagleshield and informed him that the shim had fallen out. We chatted for a while and he admitted that CZ has some serious quality problems and the President of CZ-USA is in the Czech Republic today trying to get the manufacturer to understand the magnitude of the problem. Mike said that he had tried to mount the scope on the three additional 416 Rigby rifles that he had in stock and they all had the same problem. He also said that the factory could bend the barrel to raise the point of impact but that he did not have access to the equipment here in the USA. He did not know if the source of the problem was with the action or with the barrel threads.

I also called Gene Turner with Talley Manufacturing to inquire as to whether I could machine down the front mount so as to accomplish the same thing on a permanent basis. He allowed that Talley only had .0030 metal between the mounting screws and the botton of the mount and did not recommend machining that much metal off their mounts especially with the Rigby.
Anyway, tonight I will compose a letter to the President of CZ-USA, Alice Poluchova asking for a first quality replacement or my money back. Since I leave for Mozambique on August 6, I don't expect I will have resolution before I go. I will be using my 375 H&H model 70 so I should be OK but I really wanted to hunt buffalo with the Rigby.
Thanks for all the input and please be careful if you want an American 550 Safari in 416 Rigby.

Jeff