CZ 457 chambering issue

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whiskey3

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I have a CZ 457 training model that I purchased back in the summer which seems to have a weird issue. I've been exclusively shooting CB longs and colibris to date, maybe 50-60 rounds. I recently went to sight in with CCI SV and I couldnt get the bolt closed. I thought it might be a cleaning issue with the shorter rounds leaving a residue so I cleaned the chamber and tried to manually place the full size round into the chamber. It doesnt even come close to fully seating in the chamber, protruding almost a quarter inch when it meets serious resistance. The chamber and bore look flawless, nothing wrong visually and perfectly clean.

Cant understand what the issue is here. If anyone has any thoughts I'd definitly like to hear.
 
Keep us posted what you discover - sounds like the CCI SV is running into something, whether you see that "something" or not. Do you have some way to try another brand of Long Rifle to see if that will chamber? I have marked up stuff with black jiffy marker - tried to insert - get a mark - jiffy marker scraped off - wherever it hit something - gives a clue where to inspect further...

I have a buddy's 17 HMR here with similar issue - can not chamber a round - but bore scope reveals several grooves and "thrown up" burrs along chamber walls - finally "buddy" admitted to trying to gouge grunge out of chamber with a small screw driver. So far as I know, a chamber should be shiny and smooth like a mirror. His is most definitely NOT like that!!!
 
Although I don't have that same issue, I noticed a slightly tighter bolt closure with CCI ammo. I ditched CCI and right now I exclusively shoot with Lapua SK (all available flavours) with my 457.
 
Apparently CCISV is longer than most ammo. That’s why it often shoots better than its price would predict, because the bullets engage the rifling. A tighter chamber might be too short for the CCISV.
 
Thanks for the responses. I just checked with regular Aguila and Winchester, both do the exact same thing. I have babied this rifle, definitly no screwdrivers anywhere near the chamber!

I use Ballistol and a 22 cal boresnake to clean as i dont have an undersized cleaning rod. The boresnake seems to work well. I guess I'll be in touch with CZ and see what they say, disappointing cause I hoped to get out hunting with it this season and never foresaw an issue like this.
 
Brett Olin, rimfire engineer at CCI in Idaho, confirms that the CCI driving band is longer than on other ammos. The result is that the bullet contacts the leade angle of the throat and engages the rifling before the bolt is far enough forward to close easily. Olin said CCI ammo has been designed for SAAMI chamber specs, which allow for a longer chamber than on CIP spec rifles. Most European-made rifles, such as CZ and Anschutz, for example, are CIP-spec firearms and they will have a shorter chamber than SAAMI rifles. This can result in making it harder to close the bolt when using CCI ammo in CIP chambers
 
OP - to think about - a "Bore Snake" is not really a thorough bore cleaning tool - get a real cleaning rod for that size bore. And proper brushes, jags, patches and solvents. Likely need a bore-guide as well. Not even going to guess about what might be left behind - posts above are suggesting length might be your issue - but about one way to get a chamber and bore "clean" - and despite advertising, a "bore snake" is often not the tool to use...
 
The 457 MTR has the Match chamber where the ammo seats
in the Lands sooner than others , my MTR will
not chamber any CCI ammo .

I shoot SK and RWS only in this rifle , even
then it prints on the Lands.

Not certain if your Trainer is a Match chamber
it might have lower tolerances than less expensive
ammo requires.

CCI has a great differential in rim thickness as well.
 
Agreed on the boresnake, its a stopgap measure and something I had on hand; Im going to get a .20 rod for it. I wish I had tried to chamber a regular .22 round before shooting anything as that would have been definitive. But still the barrel and chamber look very clean even with inadequate tools.

Interesting about the difference between SAAMI and CIP. I did a bunch of research before picking up the 457 and it didnt strike me that people were largely using European ammo in these guns but I may have missed that. Ive emailed CZ so waiting to see what they say.

Thanks again guys.
 
I have a 457 in a Boyds At-One stock that I just purchased new last week.
I haven't shot it yet but I did cycle a 10 round mag of CCI SV through it with no issues.
 
It could be a couple of things. I'd try gently pulling a bullet from a 22LR case, then try to chamber the unfired piece of brass.
If it won't close on that, there's a definite problem with the chamber in your rifle.
It's either not machined right, or there's a carbon ring at the front of the chamber.
CCI Stingers may not chamber because the case is slightly longer than a standard 22LR case, or so I'm told.
I shoot CCI SV in my 452 fairly often, no problems. I've never tried to fire anything except regular 22LR in my rifle.
Try a few different types of ammo.
 
emerson said:
Apparently CCISV is longer than most ammo. That’s why it often shoots better than its price would predict, because the bullets engage the rifling. A tighter chamber might be too short for the CCISV.
Click to expand...

Never had them not close in the 452's or the one 455 I have had, but yes they are a tight fit.
Length and the coating on the bullet is what I have noticed to cause this .
Maybe the chamber in the 457 is even tighter than they once where.
Rob
 
I've shot CCI SV in an Anschutz Match 54, which engraves the bullet on any ammo I've tried in it.
No reason a CZ should have any problems with it, unless the chamber is improperly machined or it has carbon buildup at the front of the chamber.
 
I have put about 100 CCISV through my 457 match chamber without issue. Winchester SV low noise, the black box with the suppressor label on it, is hard to close on mine though. I mostly use SK ammo and have zero issues with it.
 
Update to this. So I was all set to send it out to Wolverine, RMA and everything, when I thought I'd better just make absolutely sure that its not something I'm doing wrong ie. improper cleaning. So I got some Hoppes No.9 (used Ballistol before) and power swabs and went to work on the chamber. After a series of rinse and repeat I went to chamber a round and it went in. Also extracted just fine.

These CZ's must be extremely sensitive to any sort of build up in the front of the chamber. I will say that even with what must be a sqeaky clean chamber, the regular 22lr ammo that I tried still has some resistance as you drop the bolt handle down. And to that when I rechamber the same round again, it feels much easier. The bullet must be getting forced into the rifling and any offending lead shaved down making chambering easier the second time around. This is my first bolt action .22 so I dont have a point of reference, maybe all bolt .22s are similar.

So I'm happy that it's a simple fix and not a problem with CZ who seem to have a great rep for quality.
 
I have owned a couple 455s, and a lot of guys have them in our club; I still have a Brno # 2. They are all a bit snug with CCI SV, but they all are very accurate with this ammo; Federal ammo is not, but it's performance has ruled it out.. CCI Stingers are another story; way too tight in CZ and BRNO rifles.
 
whiskey3 said:
Update to this. So I was all set to send it out to Wolverine, RMA and everything, when I thought I'd better just make absolutely sure that its not something I'm doing wrong ie. improper cleaning. So I got some Hoppes No.9 (used Ballistol before) and power swabs and went to work on the chamber. After a series of rinse and repeat I went to chamber a round and it went in. Also extracted just fine.

These CZ's must be extremely sensitive to any sort of build up in the front of the chamber. I will say that even with what must be a sqeaky clean chamber, the regular 22lr ammo that I tried still has some resistance as you drop the bolt handle down. And to that when I rechamber the same round again, it feels much easier. The bullet must be getting forced into the rifling and any offending lead shaved down making chambering easier the second time around. This is my first bolt action .22 so I dont have a point of reference, maybe all bolt .22s are similar.
Click to expand...

It's good to hear it now chambers the ammo.

Readers should note that it's impossible to know if a chamber or bore is "squeaky clean" by looking at it lengthwise from either end of the barrel. A borescope is necessary to make that determination.

It's possible to develop a build-up of carbon or even lead near the chamber when cleaning is irregular or of a insufficient nature. The development of such build-ups may vary between one rifle and another and also by the particular ammo used.
 
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