CZ 457 type of match chamber

[goodi]

I have contacted CZ without success in trying determine the match chamber type in the CZ457 MTR.

Is any member able to provide specific information in regard to this inquiry?

Thanks in advance.

cheers
goodi

 

[243winxb]

Link to same problem

From instructions -
For CZ 457 cal .22 LR MATCH models (e.g. version CZ 457 Varmint MTR) Match ammunition is recommended for best firing accuracy.
In order to improve accuracy, **this cartridge chamber has its dimensions reduced to a minimum allowed by the CIP standard.** Using non-
standard ammunition (high power, longer case, longer range, etc.) is therefore not recommended. Using non-standard ammunition may case
faulty operation or damage the firearm.

Give the chamber a good cleaning? Photo & info here

 

[grauhanen]

The Czech Republic is a CIP member state. CZ is located in the Czech Republic. CZ makes its firearms, including .22LR, in conformity with CIP regulations.

CIP publishes the specs for the minimum dimensions permitted for .22LR chambers. The "CZ match chamber" is closer to the minimum dimensions allowed. What the exact dimensions of the "CZ match chamber" are is not made public.

It's worth noting that since CZ's non-match chambered firearms are expected to be able to use a wide variety of .22LR ammos, including those that may not chamber well or at all in "CZ match chambers", it can be expected that these firearms will have more generous chamber dimensions.

Below is a diagram showing the CIP .22LR dimensions.

 

[tommeboy]

All it is, is a minimum spec chamber. One thing they do also is run a 0.219"x 0.214" bore and grove. But only on the match chamber gun. i have an American version and it is 0.222"x0.219" Or as close as I can measure.

 

[Thepng]

I have a cz 452 standard sporter, think I bought it a bit before 2010. The chamber on it is super tight, and has always grabbed even match bullets and won’t extract unfired rounds. It’s amazingly accurate for what it is, so have never addressed it. Not sure if that’s a spec thing or a quality thing, but I think I have heard it’s not uncommon for Cz’s to have that issue.

 

[Lone Hunter]

I have a cz 452 standard sporter, think I bought it a bit before 2010. The chamber on it is super tight, and has always grabbed even match bullets and won’t extract unfired rounds. It’s amazingly accurate for what it is, so have never addressed it. Not sure if that’s a spec thing or a quality thing, but I think I have heard it’s not uncommon for Cz’s to have that issue.

I have a CZ 453 Varmint and like yours it will feed match ammo great but the regular blasting ammo not so much. It is a very accurate rifle with a set trigger and beautiful wood. I will see if I can find my owners manual but I believe that it said this was a match chamber and not shoot ammunition like stingers and hi velocity ammunition. Of course, this was many years ago so I probably will not be able to find it.

 

[goodi]

Thankyou to all for the insightful and informative responses.

Just what I needed to know

cheers
dave

 

[VLNBYR]

There is such a thing as a chamber cast.

 

[Conaso]

All it is, is a minimum spec chamber. One thing they do also is run a 0.219"x 0.214" bore and grove. But only on the match chamber gun. i have an American version and it is 0.222"x0.219" Or as close as I can measure.

I believe it's 0.214" x 0.219" bore and grove

 

[dusterdave173]

We use .20 cal rods, jags etc in our CZ ‘s
The bores are snug

 

[grauhanen]

I believe it's 0.214" x 0.219" bore and grove

It's not clear on what those sizes are based, but they are neither CIP nor SAAMI.

Below is a comparison of CIP and SAAMI specs provided by CZ.
CZ lands and grooves are supposed to meet CIP specs. North American factory .22LR are supposed to meet SAAMI specs.
5.38mm is 0.2118"
5.58mm is 0.2197"

5.51mm is 0.2169"
5.64mm is 0.2220"

 

[tommeboy]

From cz's faq's. This is only on their MATCH barrels. I have 2 of the regular 22lr barrels and neither is what is listed. I had a match barrel and the #;s I said above is what that one is. There is going to be a variance but these #'s are close to what a lot of others have seen also. but most people are not going to cast or slug their barrels to see what they are. They will just type a ? into google and copy and paste.

quote from cz """""I’ve heard you use tight bores in your .22s, is that right? What does that mean?
Our 22 LRs use our cold hammer forged and lapped barrels, and are built a bit tighter than many other guns. In 22 LR we run a .211 bore, which is one of the reasons our .22s are known for incredible accuracy. This also means that a .17 or .20 rod and jag are required for cleaning, since a .22 rod will be too large.

Additionally, use of .22 Short, Long and ‘Sub-Sonic’ ammunition isn’t recommended because of the tight bore. This is not to exclude quality match or target ammos, which may remain sub-sonic in speed."""""

 

[kojaone]

Who is to say it isn't a bored chamber ?
Bored chambers on CNC is faster,sharper and more consistant barrel to barrel,
several known rimfire GS's that chime on here use bored chambers.
My Modacam barrel is stamped 22lr- B, B means bored.

 

[1Merlin]

From cz's faq's. This is only on their MATCH barrels. I have 2 of the regular 22lr barrels and neither is what is listed. I had a match barrel and the #;s I said above is what that one is. There is going to be a variance but these #'s are close to what a lot of others have seen also. but most people are not going to cast or slug their barrels to see what they are. They will just type a ? into google and copy and paste.

I’ve heard you use tight bores in your .22s, is that right? What does that mean?
Our 22 LRs use our cold hammer forged and lapped barrels, and are built a bit tighter than many other guns. In 22 LR we run a .211 bore, which is one of the reasons our .22s are known for incredible accuracy. This also means that a .17 or .20 rod and jag are required for cleaning, since a .22 rod will be too large.

Additionally, use of .22 Short, Long and ‘Sub-Sonic’ ammunition isn’t recommended because of the tight bore. This is not to exclude quality match or target ammos, which may remain sub-sonic in speed.

You refer to "ours." Who is "ours?"

 

[tommeboy]

the second para is from cz's website.

 

[grauhanen]

Readers should bear in mind that despite the rounding down in the CZ FAQ answer (.211"), the CZ bore diameter remains what CIP allows, which is 5.38mm or 0.2118".

Of course actual diameters may vary anywhere through the bore.