I would just to send it straight back to the factory. After calling and making sure you follow procedure for the return. The chamber must be way out of spec to have brass splitting like you are showing.

 

Agreed, it has to be a chamber issue.

@Extremesolo, before returning it though, you can do the following without voiding any warranty. Look at where the barrel meets the receiver. Is there a noticeable gap? Even if there isn't, pull the barreled action out of the stock and ensure that the (2) screws on the underside are torqued to 35 inch pounds.
Does your bolt close on an empty chamber with a slight hydraulic resistance feel? Excess headspacing can cause those necks to crack on a 17.

 

I totally agree with 1Merlin. Send it back. I don’t believe the test targets that they send. Send them a couple of fired cases and/or a couple of pics. Your gun has a problem.

 

Excellent advice. True, there is MUCH ( too much ) ammo variability in 17HMR, but this appears WAY off.

 

I have one that has never had a split case and is more accurate than I am.

Send it back without delay.

 

Return it

 

Are you sure you aren’t shooting a WMR?

 

I almost posted this question too.
It's a definite maybe.

 

I`ll make it unanimous. Somethins` broke! Send her back.

 

If it isn't old ammo I'd send it back.

 

A .22 WMR chamber is unlikely folks, but I agree there is apt to be a chamber problem unless that is some ole ammo, some of which had splitting problems. Call CZ (don't text or email) and tell them what is happening, that's why Companies have warrantees.

 

That looks like very old ammo. Try some newer stuff. Some of the first ammo had issues.

 

Following

 

I've got some older Hornady V-Max and I get some splits from that.
The accuracy isn't as bad as the posters though. Never 2" at 50 yards......

 

Measure the fired cases, compare them to unfired cases, neck dia and shoulder dia. If the cases are dramatically increased in diameter then it's a chamber issue, if expansion is only a few thousandths then it's an ammo issue. I have a HM2 that suffered with these issues as well. The cases expanded only about 0.002" but split cases occurred about every other round. The last couple lots of ammo have been without issue and shoot great. CCI admitted having an issue with case annealing, in that they had to apply the priming compound prior to neck sizing the wmr case, same for the lr case the hm2 uses, resulting in work hardening of the brass. Now they have an unnamed method of annealing, after priming, that uses no heat. So it is possible, if not likely, that it is an ammo issue.

 

Sorry buddy, but you got a lemon. I've never heard of a 17HMR shooting that badly, let alone a CZ. I've owned six 17HMRs and all shot much better than yours. Send that dog back!

 

I called CZ and was told to fill out their warranty claim portion of their web site to get it sent back to them. I did that yesterday but have not heard anything back from them yet. I will update once I get more info.

 

Don’t get yourselves all offended that the OP has not responded. It could be that he has sent the rifle in for warranty and that is the only thing that has transpired so far.

 

That gun has big problem. No doubt. Hope they get you fixed up. No need to measure anything. The cases splitting is the tell all. And monster sized groups at 50 yards. I would want to see 1/2” groups at 50 yards or maybe better.

 

My Savage .17HMR has been splitting cases for over 15 years and will keep every round inside a dime at 100 yards and will hit a milk jug at 250 yards. At the time everyone was getting split cases. This is the first I'm hearing of an accuracy issue. At the time everyone was saying that it was (OLD) ammo. I don't know about old ammo causing such issues no matter what caliber. I have plenty of 30+-year-old ammo with no issues in various calibers. I never heard of any resolution to the split case issue, and since I got my .17WSM I don't take the HMR out very often. My bigger issue is the empty cases getting stuck in the chamber and I'd have to carry around a small screwdriver to pry them out. Not too big a problem seeing as I used the gun primarily on woodchucks and with its accuracy, you never needed a backup shot.

 

My 17 hm2 as far as a round being correct poinwise with split case is hit and miss (at 72 yards). Where I was shooting targets with what few I have had split.

I purchased a Savage back in 2004 in hmr. It never ever split a case. Shot gun for 5 years. Only shot hornady through it -17 grain vmax. And it shot real real good. My neighbor has the gun now. I sold it to him. Like a dummy. Lol. It was hard on my ears for squirrel hunting. I didn’t like that part.

 

I have the same guns. I threaded both for a can. Same accuracy results as you too, and the very same impact on the squirrels. The squirrels were not the same as yours though.

More recently got a 457 At-One in .22 lr and an aftermarket Walther Lothar 17 HMR barrel. The squirrels are all hibernating.

 

The only .17HMR rifle i have now is a Ruger 77/17. Never had a single neck split using CCI, Browning or Winchester polymer tip and hollow tip and I have blown through 250 rounds since purchasing it.

Accuracy from the 77/17 is more than adequate to giterdun. Love this rifle more than perhaps I should. Elegant, slick, accurate and just right.

What's this got to do with cz457s? Nothing. Simply nothing I had an HMR CZ452 Varmint and liked it...but not loved it.

 

Based on my experience, the problem is the ammo. Over here in Aus the batches of ammo are typically pretty old & because the necks on these cases cannot be annealed they are too brittle causing neck splits & the age of the brass just adds more grief. All that pressure lost in creating a split neck is what’s causing the inconsistency. My ammo failure rate was at least 20% & I tried various brands with none standing out as better than the others. The rifle came with a decent group test card from cz, so I had no reason to question the rifles integrity, I gave up on .17hmr & now have two .22lr one for bench (cz457) & one for hunting (Ruger) plus a (Ruger) .22wmr for longer range bunny bashing & don’t miss the .17hmr as these all shoot way better than I can. So .17hmr did me a favour as I now have three rimfire instead of one.😁

 

I have 800 rounds of .17HMR currently and none is older than 2022.

 

I have some Winchester Super X 17 HMR. 17 grain. Tried it out in my 457 Lux and groupings were horrible. All over the target. I was confused because the groups when shooting as of my CCI ammo grouped fantastic. I checked the spent casings after I shot the Super X and almost all 25 rounds I shot kicked out splits. I don’t shoot that stuff anymore. Wouldn’t even give it away.

 

It could be a headspace problem. I would remove the barrel and do a thorough job of cleaning the barrel recess in the receiver, and then clean the exterior of the barrel where it goes into the receiver as well as the breech face. The bolt should feel snug and make very slight contact with the case head as it closes. You can use a permanent marker to put some ink on the cartridge head and rim, then insert it into the breech of the rifle manually, close the bolt, and then open the bolt to eject the cartridge. Check to see where there was contact... it should be pretty good on the base of the cartridge as well as on the rim on the chamber side.

Most of the test targets from these guns weren't put very far out.

I have a CZ 452 in .17 HMR and a CZ 455 with the factory HMR barrel... both are under 1" at 100 yards with Hornady, CCI, and Federal ammo. The 455 and 457 use the same takedown barrel design. If the above doesn't help, how does the rifle shoot with a .22 barrel? Or, you could just send the rifle back to CZ USA and let them deal with it.

 

OP hasn't been back since Oct.
Love how OPs 'drop' the thread with no resolution.

 

OP hasn't been back since Oct.
Love how OPs 'drop' the thread with no resolution.

I had a one night stand girlfriend like that, oh well. Dang but she was a looker though. sigh!

 

I'm hoping the OP does get a satisfactory resolution. Something like his problem could totally sour you on a rifle and/or manufacturer. I've had stuff like this drag on for entirely to long as it filters through the bureaucracy of a company.

 

Indeed. I purchased a 457 Training rifle that shot terribly with open sights. I thought about selling or trading her off. Tried a variety of different ammo and found the right stuff. Glad I didn’t get rid of her. Shoots great if I can.

 

I would check action screws .