I just built a mandrel for a CZ 550 to check the alignment from receiver centerline to scope centerline. The threads are a very close fit. When tightening up by hand the shoulder of the mandrel contacts the top of the receiver ring first. There is a .013" gap between the shoulder and the bottom of the receiver ring. When I put a set of rings on the action and install a 1" ground bar in the rings I can see the angle between the mandrel and the scope rod. The false barrel mandrel is pointing up hill BIG TIME!!!!! The taper is .137" per 12". In 100 yards this adds up to over 40". This means the threads are in crooked but the c-ring and receiver ring are close to where they should be.

Has anyone else had problems with CZ actions having JUNK threads?

I have posted many, many times on this forum and the big bore forum that soemthing is amiss with the big bore CZ's. When calculating the required heights for iron sights, I typically find them AT LEAST 12" low at 25 yards. That means they hit at least 4 FEET low at 100 yards. It is very typical for scopes to run out of vertical adjustment and still not be hitting the point of aim.

I never knew exactly what caused it, but always figured it had to do with the barrel being screwed in all cocked up. I know one thing, there is absolutely zero reason for CZ to screw in the barrels as tight as they do. It is rediculous how much I turn off the factory shoulder when reinstalling the barrel.

This is bad news.

But on the other hand, perhaps this is the info I needed to make a decision between a Charles Daly mini action and a CZ 527.

I'm wondering if this flaw exists with my action, and if so can it be determined without pulling the barrel? Perhaps by trying the iron sights that come with the CZ 527 to see if it shoots high or low, as if the barrel is not properly aligned with the receiver?

KB

I don't think it would make much difference on open sights.

Kabluewy: read some threads on the CZ 527 and you'll see the vast majority of them are about the accuracy of the rifle. Besides, the CZ 550 and CZ 527 are two different actions. I have a CZ 550 American in 7x57mm which routinely shoots half inch and sub half inch groups at 100 yards with no sweat. I think the gentlemen are talking about the big bore grade of rifles built here in the United States.

quote:

Originally posted by gunmaker:
The threads are a very close fit. When tightening up by hand the shoulder of the mandrel contacts the top of the receiver ring first. There is a .013" gap between the shoulder and the bottom of the receiver ring.

Perhaps if you induce a little slop in the barrels threads, the barrel may pull up straight when it contacts the receivers face. Assuming of course that it is square to the bolt.

quote:

Originally posted by 7x57mm:
Kabluewy: read some threads on the CZ 527 and you'll see the vast majority of them are about the accuracy of the rifle. Besides, the CZ 550 and CZ 527 are two different actions. I have a CZ 550 American in 7x57mm which routinely shoots half inch and sub half inch groups at 100 yards with no sweat. I think the gentlemen are talking about the big bore grade of rifles built here in the United States.

Thanks for reminding me of all the good reports. Actually, within my memory, this is the first I've read anything significantly negative about the CZs. Personally, I have shot two of the 550s in 9.3x62, and both produced excellent results at the range. They were easy to sight in, and accurate. Also, I have heard good reports from two other friends that their 9.3x62s produced similar results. Another friend had a 300 win mag in the big magnum action that was good with the factory barrel, and with the 416 Rem replacement barrel. The gunsmith did not mention any trouble installing the new barrel. Anyway, I'm committed to the 527, so I'll test it carefully, and see what happens.

KB

I have built seven rifles. for 1 customer, all based on CZ527 actions. Most are wildcats on the Hornet case and the others are on the 218 bee and PPC case. I ordered a trueing mandrel from PTG and squared up all of the actions. The Lilja barrels were fitted with a shoulder mated up to the front of the receiver only. I was amazed at the consistancy of these little actions. Headspace, on the last three was within .001". When squaring up the front of the actions I removed .015" from each action. I'm really impressed with the quality of workmanship, the single set trigger and the price of this action.

eddie,

You had to remove .015" to get the receiver face true? Am I reading your post right?

No, I removed .015" to create a adequate face for the barrel shoulder to snug up to. They come from the factory with a very narrow, almost sharp, face on the receiver. They are sort of like a Mauser with an inner "stop" for the barrel shank to snug up to. I chose to face the receiver and let the barrel snug up like other types of actions.

quote:

Originally posted by Kabluewy:
This is bad news.

But on the other hand, perhaps this is the info I needed to make a decision between a Charles Daly mini action and a CZ 527.

I'm wondering if this flaw exists with my action, and if so can it be determined without pulling the barrel? Perhaps by trying the iron sights that come with the CZ 527 to see if it shoots high or low, as if the barrel is not properly aligned with the receiver?
KB

I have a 527 in 7.62X39mm that shoots like this:



And a 550 in .416 Rigby that shoots like this: (Center hole was with a 400-grain jacketed load to see if the gun was on paper. Upper right three were with 350-grain CAST GASCHECK BULLETS at 2150 FPS using 112 grains of AA8700 with F215 primers.)



I don't know if the barrel threads are straight or crooked, but I had no trouble zeroing either rifle.

James,

Are these cz550 actions with the misaligned threads able to be fixed?

Is it even worth working on a receiver in this condition...?

There has been a fair bit of talk on these forums about this issue and I am wondering what
one can or should do in this case.

Best,
Dave

quote:

Originally posted by eddieharren:
No, I removed .015" to create a adequate face for the barrel shoulder to snug up to. They come from the factory with a very narrow, almost sharp, face on the receiver. They are sort of like a Mauser with an inner "stop" for the barrel shank to snug up to. I chose to face the receiver and let the barrel snug up like other types of actions.

Eddie,

Are not these Mauser actions designed for the barrel to abut and stop at the inner C or H ring and not the face of the receiver? Correct me if wrong. I may be interpreting what you write incorrectly.

Stephen


Thanks

The inner ring is neither an H or a C, like a mauser, but a very small ring, that in my estimation, did not provide an adequate surface for the barrel stub to lock up on. My customer orders his Lilja barrels with a contour that allows me to turn the shank portion to 1.1" prior to turning and threading. After I true the face, as described above, there is an adequate surface for the barrel to mate to the receiver face.

This is an old thread..

I haven't had any more CZ actions through the shop. The threads could be re cut with a big fixture like the benchrest guys use on Rem700s. C ring & metric thread would make the process take more time $$.

quote:

Originally posted by DocEd:
The inner ring is neither an H or a C, like a mauser, but a very small ring, that in my estimation, did not provide an adequate surface for the barrel stub to lock up on. My customer orders his Lilja barrels with a contour that allows me to turn the shank portion to 1.1" prior to turning and threading. After I true the face, as described above, there is an adequate surface for the barrel to mate to the receiver face.

Thanks for the clarification. The barrel has to stop against something, eh?

Stephen

If I may, I have seen posts by several gunsmiths, here and on other boards, who routinely fit barrels to the front of the receiver rather than on the C ring.

I'm surprised Brno/CZ has had this problem so long. I have heard of others having the same problem. My own 1985 Brno 602 in 375 H&H shoots 8" low after running out of scope adjustment, and I tried a couple of different scopes. You would figure the first owner would have complained about the inability to zero the rifle. My CZ550 in 416 Rigby seems to be OK.

I've E-mailed Burris to see if their CZ rings come with their pos-aline offset inserts. Have not heard back from them yet.

Hart

Other than the time and money what sort of results can be expected....?

....workable or so so in quality or fully corrected and precise?

I just don't have an understanding regarding how this correction works and less so for the quality of the end results.

Thanks,
Dave

Harald Wolf of Hatari Times has said he couldnt understand why the CZ got used as often as it did for custom work as they were so poorly made, they couldnt be made right.

I think Mr. Wolf's comments are a bit harsh!

Harald is a topshelf gunsmith who for a while was building best quality Mauser actions by hand out of bar stock. They were designed to be a perfect fit for the 500 Jeffery. I believed he stopped making them due to the cost he had to charge for them. They were amazing pieces of work!!!

Did he site any specific points of concern regrading his "poorly made" comments?

I really love to learn what he felt were flaws that needed to be addresses. It would be very helpful information coming from someone of his skill...!

There are a lot of cz550s out there and while they have their weak points for sure I don't see them as being much different than a Remington, Ruger or Winchester in that repect. I think they all need "work" to bring out the best in them....


Best,
Dave

Dave,
He said it takes more to make a quality gun then a bit of polishing and a nice stock, that with the cz you could polish off, but couldnt polish on where there wasnt any.
Basicly, the tolerances just wer'nt very good.