Sure looks like a defect to me!

 

I have a non-modified CZ 457 MTR. Been shooting it about a year. I always thought it was not reaching it's potential at 50 yards with match grade ammo (SK Rifle Match, SK LR, Eley Match). So, I bought a bore scope (also so I could check carbon rings, etc., on all my .22's). I found this about 2 inches down the barrel from the chamber. It goes 360 degrees around the inside of the barrel through the lands and grooves.

I sent pics to CZ USA. They said to send it in for repairs. I got it back with a note that they did not perform repairs. They said this was an artifact of cold hammer production manufacturing processes.

I was really hoping to keep this gun factory original for competitions. But now I am thinking of replacing the barrel and rebuilding it.

Anyone ever see this in a CZ 457 MTR barrel? Insights are appreciated.



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My American has similar lines but, those seem a little worse. There was a thread here a week or so again where somebody saw something very similar in their barrel and most people said it was normal and a result of the barrel making process.

This is the thread

https://www.rimfirecentral.com/threads/first-borescope-pics-and-what-is-this.1313040/page-2?post_id=13526213&nested_view=1&sortby=oldest#post-13526213

 

Both of mine have similar marks.

 

My 24” match barrel had some marks like those visible in the grooves of your barrel. It shot well and didn’t seem to be affected by the very shallow, transverse irregularities. But, that divot in the land of your barrel looks pretty gnarly and I don’t see how it can be a good thing. I think CZ owes you a barrel. But, if they won’t come through, you could always swap it out. I put a 26” Whidden/Mullerworks on mine.

 

I just checked my new (never cleaned or fired) Scout and it had similar marks at about 2" from the breach.

 

WG - I checked some of my old Bore-vids ( I save all that stuff for posteriority) and found a few 'traces' of that sort of thing. I bought the rifle with ca 500 shots but didn't see anything. In earlier vids the bore seems 'glazed' with 'seasoning' that I pretty much removed now, so nothing show back then. My rifle has ca 2500 rounds and still gets 0.3-5xx with good ammo. Don't know what you want to do but this is good for me.
Here's a pic from last summer -

 

Throw the borescope away.

 

That's what my Reminton 504 barrel looked like inside. It shot like crap. I put a new Barrel on.

 

I had one a few years back that had the chamber off center sent to CZ America they said it was with in there tolerance for a CZ rim fire rifle I rebarreled it and sold it to never to own another CZ.Others on here have had good luck with CZ but not me.

 

I had one a few years back that had the chamber off center sent to CZ America they said it was with in there tolerance for a CZ rim fire rifle I rebarreled it and sold it to never to own another CZ. Others on here have had good luck with CZ but not me.

CZ457 MTR
Manners CF stock
Timney trigger 2.5oz
Lilja barrel 20"
Athlon Ares ETR UHD 4.5X30X56 MIL APRS1 FFP IR MIL RETICLE
Atlas bipod on ARCA Rail
Protektor rear bag
Lapua OSP for 50 yds, Center X for 100 yds, for 200 and 300yds, Lapua Long Range
I do not shoot groups except for a sight in because of shooting Cards, that's what I shoot in practice, I think it is a lot easier to shoot good groups and much harder
Shooting 4 cards in a match where only one shot is allowed for each target. Last weekend I shot a match with shifting wind and managed a 2500 on three of the four
Cards, I dropped one shot

to a 50.

 

What you're saying in the picture....

1. It's obvious it's a hammer for its barrel
2. The defect in the lands and the groove strongly suggests a tool mark from drilling and reaming.

 

Bore scopes can be the best thing ever, or the worst!😂

 

The rifling in these barrels is cold hammer forged using a mandrel and it's always been my opinion that the marks the OP posted are the end of the mandrel where the barrel was hammered and something allowed a gap that should not be there. Watching a video on cold hammer forged rifling will show very clearly what I'm referencing.

 

For what you pay for one the inside of the barrel should be as smooth as your eyeball

 

I have a bunch of those. They're called "shotguns".

 

I've watched a couple vids of HF and when they get to the chamber the mandrel 'end' is about 3" out from that and that's about where the OP's marks are. Seems inherent to me. JMO - - - There's links to many vids here -

 

Got me there

 

Thanks everyone.

 

Yep, borescopes will worry you to death.
Now i only use mine to look for leading after cleaning my revolvers and for copper in cfire rifles

 

Borescopes are a tool and like any other tool you have to use it properly and you have to know what you are looking at. That said, if CZ won't replace the barrel and you think it's defective, take it to a couple of respectable gunsmiths and get their opinions. I have seen worse marks in a barrel than what the OP has and they shot very well. If the gunsmiths that look at the barrel say it is trash then trash it or sell the gun. Very simple solution. Let's remember here CZ is NOT a high end rifle in the true sense of the term. Quite simply almost all barrels new or old have marks of some sort in them. The higher quality makers strive to produce barrels with almost perfect interiors, but this is difficult to do. Those same high quality manufactures spend time lapping barrels for an even better finish. The problem is lapping a barrel is extra labor which equates to extra money. How much do you want to spend on a rifle?

And if anyone wants to throw away your functioning borescope throw them my way. I'll be happy to take them as long as they work.

Rick H.

 

wgalvanized, With several long-time members saying their rifles have similar marks, I'd not worry more unless it shoots like Fuzedude's smoothbore. Just keep looking at the chamber to watch for Carbon and buy some C4. Anything is better than Hoppes #9 since they 'de-toxified' it; 'H' does make more 'serious' solvents. And most serious shooters will clean the bore often so you have a consistent lube condition. My 457-VMTR loses accuracy around 100-150 rounds, using SK-RM. I don't run the cheap stuff in my CZs.

 

I have a non-modified CZ 457 MTR. Been shooting it about a year. I always thought it was not reaching it's potential at 50 yards with match grade ammo (SK Rifle Match, SK LR, Eley Match). So, I bought a bore scope (also so I could check carbon rings, etc., on all my .22's). I found this about 2 inches down the barrel from the chamber. It goes 360 degrees around the inside of the barrel through the lands and grooves.

I sent pics to CZ USA. They said to send it in for repairs. I got it back with a note that they did not perform repairs. They said this was an artifact of cold hammer production manufacturing processes.

I was really hoping to keep this gun factory original for competitions. But now I am thinking of replacing the barrel and rebuilding it.

Anyone ever see this in a CZ 457 MTR barrel? Insights are appreciated.



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I've been thinking long and hard on this for a couple of days. I've just bought a 457 varmint and have had a bore scope on order for about week now to keep tabs on the barrels (.22 and .22WMR).

I'll be pretty disappointed if I have hammer forge marks as deep as those on the varmint barrels, however CZ don't seem to think it's a big issue even for the match barrel.

I notice that your barrel is spotlessly clean. That's a credit to you, however this is not what everyone recommends. Some say to never clean by which they mean never clean unless it affects accuracy. The reason for this is leading of the barrel will cover many imperfections like these and aid accuracy. Using a lead solvent should be reserved for the more extreme cleaning requirements. Try not cleaning for a while except for basic carbon fouling (I'll describe my method below). I've never believed in it, but I'm starting to think there might be something in it after all, especially since that's what I've always done anyway.

I've noticed top level match shooters do clean rigorously every hundred rounds or so to this level (not a skerric left in the barrel) but they always fire some fouling rounds before going back to shooting scoring rounds to "foul" the barrel again. That's on polished match barrels that probably cost much more than my 457 and two Varmint barrels.

How long does the leading process take? Well some people say five or six rounds, others say as many as three hundred. You know, ask 10 shooters their opinion on something and you'll get 12 different answers. I think it may depend on the barrel, but also on the perceptions of the shooter, but I seriously doubt there's much difference in leading between twenty rounds and three hundred for most people.

Try not cleaning with lead solvents for a while, maybe it will help you. I did notice that some rounds (CCI MiniMag HP) did group terrible at first, but after some sixty rounds or so on the new barrel, when I went back and retested them they started to group closer to the sub-MOA that I was looking for.

My cleaning: I use the old machinists cleaning lubricant for most things and always have. It's half mineral oil (white oil) and half paraffin. Save the heavy duty solvents like lead and copper removers for when they are really required.

The paraffin acts as a solvent and lets you remove all of the carbon in the barrel, though the reason I'm getting the bore scope is to keep an eye out for a carbon ring forming. This can crimp the bullet and cause increased pressures and inaccuracies. Carbon particles can also form hard deposits that can score the barrel, so cleaning is still important, you just don't necessarily want to be using a lead solvent.

So, maybe don't give up on that barrel. Lead it in. I also think that after not shooting for a very long time (decades) I have to work on my hold a little bit. The two things that made the biggest difference to my groups on Sunday was concentrating on my hold, and watching the wind. The right ammo did help a bit too. Basically I knew my aim point was good and the scope was zeroed and acting consistently, but if that was all that was required there'd be no difference between me and the comp winning match shooters that were in the same line as me.

 

From what I've read, 'Match shooters' clean nearly every card, which means ca 30-40 rounds depending on amount of sighters fired per card. And Fouling only 5-10 rounds is common. This is to 'build up' some lube, Not Lead. A carbon ring can affect bullets passing thru, developing from 100-rounds onward. I keep Boretech C4 in a small 'eye-dropper bottle' in my range bag, as well as patches and a rod. Run this thru every 50-ish rounds too keep buildup to a minimum. It doesn't remove all of the 'seasoning' but does take away some carbon and primer debris.
As for the 'forging mark' in @wgalv... barrel, I have worse marked barrels that do MOA or better.

 

The point is, match shooters really do clean right down to bare metal. A lot. For example Speedy:

Note that I'm not recommending people do this, unless you're a high level match shooter in which case you're probably already well on the way.

It doesn't matter what these guys "say", leading does occur on fouling rounds. My point is that for the rest of us shooting factory barrels, removing absolutely everything may not result in perfect or even good groups. If someone is having trouble getting groups with a factory barrel that is generally considered very good and they are presenting with a pristine barrel, then maybe try NOT cleaning down to bare metal every single time. Leave these aggressive solvents for when you really do need to clean right down to bare metal for a reset.

It doesn't make sense to continue to do the same thing and expect different results.

 

I just bought a new mtr and decided to inspect bore prior to shooting and starting halfway down bore light tool marks in a circular pattern. They repeat frequently and get deeper and more pronounced as you get closer to chamber. Contacted customer service and waiting for repair authorization to have inspected. I am totally bummed to see they didnt do anything for you and said yours is completely acceptable. Cz website brags on smooth bore and crisp rifling, guess they are full of crap

 

How does it shoot?

 

Have not shot yet and have been hesitant to shoot. Was hard to aquire a variety of match ammo in anticipation of testing. Dont want to waste. After seeing the tool marks which get fairly significant as you get closer to the chamber. I dont know, it may shoot ok but i will always question if issues are ammo or bore condition. Thats why i submitted a warrenty request to cz but have not been contacted back. I always heard good things about cz which is why I am disappointed in quialty control

 

It's not so much quality control as an artifact of the method of production. Considering that hammer forged barrels are considered to be quite good, regardless of what it looks like you should shoot and see what happens. You don't really have a case for warranty unless you can also say it's not shooting right. Like others have intimated, it's a trap to think that how a barrel looks is significant when it comes to accuracy. It's not like the crease from the mandrel is going to score the bullet or anything.

CZ guarantee sub MOA and I believe they test the barrels in the factory.

What I found was mine shot good out of the box with subsonics, but some of the rounds that were problematic early on started to shoot better after a few groups and certainly by the end of the first range day.

It went something like this: I cleaned the gun when I got it in case there was cosmolene or something in the barrel. I then forgot to dry swab it on the range day due to excitement to put rounds down range. The first two sighters were an inch apart, but consistent enough to make an adjustment. The next three was a 1/4" group and after another adjustment it shot another 1/3" group all at 50 meters. The safety officer was gob smacked.

At that point the wind picked up and I wasn't doing such a good job of it but that was down to me. Just go and shoot it, I think you'll be pleased.

 

I have a MTR new also. I’m going to shoot it first and see how it does before I jump in and bore scope it..I’m a little nervous to see what it looks like before I know it can or can’t shoot well…found this out by bore scoping my new varmint first..

 

Though the marks in the OP's barrel are fairly obvious, I can't say whether they will affect accuracy or leading or not.

I've had a borescope for about a year now. One thing I've learned is that I can't correlate how a barrel looks with how well it shoots. My Dad and I each recently purchased CMP 40X's. I was worried about how Dad's was going to shoot. The chamber was quite rough and the last inch or so near the crown looked to be somewhat polished by a cleaning rod. His 1st outing had a 5 shots, 10 group average with SK Semi Auto in the low .3s. He shot a 5 group average with another lot that averaged .299. I'm not sure it can get much better than that with that ammo in 40 degree temps.

I thought the crowns on my last two rifles were going to need to be reworked. Both of them shoot so well I wouldn't think about touching them.

My brand new Anschutz had some tooling marks periodically along the length of the whole barrel. It shoots as well as I'd expect it to.

I'm sure the more experienced can scope a barrel and have a good idea if it will shoot or not. I've learned that I can't.

OP, what kind of accuracy/groups are you getting with your MTR?

 

No I have not seen that but I will now look at my CZ MTR Barrel with the borescope. thanks for the headsup