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CZ 452 2ZKM American Inaccuracy .17HMR


R6demon
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4 hours ago, Ultrastu said:

I agree with above .

Ive had duff scopes  

Go off zero then back on again.

Back and forward .as you shoot .

Scopes   have  small springs (coil or leaf ) that rely on friction to stay in place..

Recoil can easily effect the zero .as it changes the friction .if your scope is far from optical or mechanical zero .

(Optical is when the x hairs are dead centre of the front lens element - as far as the polishing ground is concerned )

Mechanical is when its centre of the scope tube (and should be  when your at the centre point in terms of clicks of the turrets up / down  left /right .  But not always .)

If you have had to crank a turret loads up or left or other to zero .Then you wont be looking through optical centre and the pressure on the internal adjuster springs can be either too much or little making the  adjusters of the internal optic that has the x hairs etched onto it .move from shot to shot .

You are of course, the holy grail of all knowledge Ultrastu. However, sometimes it helps to look at the evidence. The op has two magazines. Look at the op, 2nd paragraph. It’s the latter rounds in the mag that are the issue not the first fired. So I suggested he cycle a mag. Result was damaged cases before being fired. The scope he has is a good quality scope. Ok, all scopes irrespective of cost can develope a fault. But recoil on an hmr, really? The op has exhausted and proven it’s not moderator, floating barrel and all the other endless suggestions people come up with, including, patronisingly, the ability of the op to shoot accurately. I had all these well meaning suggestions with mine which was displaying exactly the same symptoms which is why I made my suggestions. As a consequence, a problem has been discovered. If you choose to ignore that and the evidence of series of events, then that’s a matter for you, but your input in that regard is not a help to the op and his problem.

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Turbo .

Thats a very un nessesary dig at me .

I truly dont know the cause of his issues .i dont have much in the way of hmr experience .and will leave that to others with more .

My post was just to high light how scopes can jump and its worrh considering in his quest for a solution. 

No one is saying that your posts are invalid or wrong..to be honest i cant remember what you wrote .

We are all trying to help and id guess the op is happy to hear  more than just one possible explanation.

Ps  to the op .  I tend to find that with a very tricky to diagnose accuracy issue 

You may have more than one problem this just makes the diagnosis  even harder .again worth considering .

 

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2 minutes ago, turbo33 said:
4 hours ago, Ultrastu said:

I agree with above .

Ive had duff scopes  

Go off zero then back on again.

Back and forward .as you shoot .

Scopes   have  small springs (coil or leaf ) that rely on friction to stay in place..

Recoil can easily effect the zero .as it changes the friction .if your scope is far from optical or mechanical zero .

(Optical is when the x hairs are dead centre of the front lens element - as far as the polishing ground is concerned )

Mechanical is when its centre of the scope tube (and should be  when your at the centre point in terms of clicks of the turrets up / down  left /right .  But not always .)

If you have had to crank a turret loads up or left or other to zero .Then you wont be looking through optical centre and the pressure on the internal adjuster springs can be either too much or little making the  adjusters of the internal optic that has the x hairs etched onto it .move from shot to shot .

You are of course, the holy grail of all knowledge Ultrastu. However, sometimes it helps to look at the evidence. The op has two magazines. Look at the op, 2nd paragraph. It’s the latter rounds in the mag that are the issue not the first fired. So I suggested he cycle a mag. Result was damaged cases before being fired. The scope he has is a good quality scope. Ok, all scopes irrespective of cost can develope a fault. But recoil on an hmr, really? The op has exhausted and proven it’s not moderator, floating barrel and all the other endless suggestions people come up with, including, patronisingly, the ability of the op to shoot accurately. I had all these well meaning suggestions with mine which was displaying exactly the same symptoms which is why I made my suggestions. As a consequence, a problem has been discovered. If you choose to ignore that and the evidence of series of events, then that’s a matter for you, but your input in that regard is not a help to the op and his problem.

To the OP.  I completely understand your frustration, and with the plethora of well meaning helpful suggestions here, are now probably thinking an hmr is the most complicated rifle to shoot, and only the most skilled snipers with military training and an endless supply of high quality, recoil proof equipment will succeed in being able to shoot it with any acceptable degree of accuracy! You’ve identified a problem, investigate that and I’m sure it will be fine.

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4 minutes ago, Ultrastu said:

Turbo .

Thats a very un nessesary dig at me .

I truly dont know the cause of his issues .i dont have much in the way of hmr experience .and will leave that to others with more .

My post was just to high light how scopes can jump and its worrh considering in his quest for a solution. 

No one is saying that your posts are invalid or wrong..to be honest i cant remember what you wrote .

We are all trying to help and id guess the op is happy to hear  more than just one possible explanation.

Ps  to the op .  I tend to find that with a very tricky to diagnose accuracy issue 

You may have more than one problem this just makes the diagnosis  even harder .again worth considering .

 

I understand people want to help. But honestly, I’ve been there with the hmr, and asked for help here. I had the same replies. Changed two scopes, oh it’s def your scope mate, changed mods twice and fired without a mod, oh your rounds are clipping your mod, pulling your shots, need a trigger kit, your barrel needs free floating, you nee lessons, the list goes on. what on earth was the point of ignoring the one peice of evidence of a fault, and backing up another probability when you say you have little experience of the rifle! 

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Guys thank you for the continued support! I have a spare Optisan scope on my LR so I will start by swapping them over. The MTC scopes have been very good to me in the past, the optics are very clear and I have never had an issue (up until now perhaps!) I’ve certainly never felt the need to spend ££££ on a scope to shoot at 100m especially as most of my shooting is through an LCD screen (NV)

I understood that casings and the condition were critical in CF, Is this not the case in RF Turbo?

its interesting to know how the scope works Ultrastu thank you. I will reset the turrets and see how far off I am!

I saw the comment about shooting with the least human interaction and I certainly understand this! When I had the use of the driving range locally, I would set up the Site and Clean gun rest with the rifle strapped down and Zero that way, it makes a big difference especially when attempting a 2 shot zero. I also believe that I shoot far more accurately looking through the NV for the same reason! It’s also more comfortable that way. 
 

I am certainly No marksman, but I believe I owe it to my quarry to be able to shoot head shots up to 100m, without that confidence in my kit and ability I will not go out. 
 

regarding moderators, is there much difference between them? I have a SAK that I bought new on my .22 LR bit haven’t seen much difference between the generic one that came on the .17 and the SAK?
 

 

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I had a 452 American Hmr with wood stock,full length barrel & SAK mod for 12yrs.ILike you,I could never get a clean patch when cleaning and cleaned after every outing .The only hiccup in accuracy was after about a year the wood started to touch the barrel but a light sanding of the channel sorted that.I went through 4 different scopes ,eventually had the barrel shortened ( which made no difference accuracy wise) but it was and still is perfectly accurate. I`m sure there shall be a fairly straightforward to your problem and can understand the frustration ! Its a process of elimination ! Best of luck.

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I would look at getting a bore scope,

 

My suspicion is, ammo, scope, crown, mounts.

Teslong make a USB bore scope available on amazon for £46  and is worth every penny (although on second thoughts maybe not, as you will be horrified at the state of some of the bores.)

 

Also a Torque driver as the stock screw tightness can really effect accuracy in a big way. I settled on 18 nm front and rear and the groups shrank. Its like a wierd form of zeroing but with a torque driver. Again Amazon for Laser tools bicycle torque  driver for 30 squids. 

 

HMR has a mixed reputation for accuracy, there are numerous reports from the states with some pretty scary results and even a couple of detonations there have been many bad batches which are finding ther way over here.

Added to that, some of the more recent CZ's have quality control issues. Namely rough bores and chambers and poorly finished crowns.

I had 2 452's that couldn't shoot the floor if i tried but i got very lucky with my 455 American, with a poor crown but for some reason it shoots like a charm, although I'm going to lap the muzzle with a gunsmiths tool just because its been niggling me.

 

MTC make some good scopes but they have a knack of losing zero after a few years. I have had two and my club members have sent a couple back as they lost zero, the repeatability of the turrets can be hit and miss too.

 

I gave up on MTC a few years ago, I only use Nikon due to the large amount of fake leupolds being sold by "unsuspecting" gun shops. 

 

Meopta, Shimdt, and Nikon are the only scopes worth bothering with.

 

I know a few guys with March 50x scopes and to be frank it feels like the emperors new clothes especially on a Ruger 10/22 

 

Personally I would invest in a Nikon and be 100% sure get some decent ring,  such as B Square steel rimfire rings 

 

Hope this helps!

Edited by Discontinued
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Have you tried to feed the rounds directly in to the chamber not using the magazine. This will discount the damage being don’t you the round.  Ensure you push the round into the chamber by hand not using the bolt so the bolt magazine interface don’t do other damage to the rounds.  
 

if you suddenly get good groups of 5-10 shots it proves it’s a magazine feed issue. 

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I too have a 452 American with a SAK moderator and it can be a tack driver.

I do not wish to antagonise any of the previous posters as the info given can and may be valid.

I have a number of shooting pals who have various manufactured HMRs and there is no doubt that after 20 or so rounds the accuracy can drift. Most of us now carry a pull through and use it a couple of times and hey presto back to normal. The HMR is a dirty round and a quick pull through isn't going to hurt. I no longer bother doing strip down cleans with copper cleaner or patches.  As a matter of fact at the end of my shooting sessions, I am doing the same thing with my CF rifles as well.

I look forward to hearing what the final outcome is, good luck with your experimentation.

FB

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4 hours ago, Discontinued said:

Teslong make a USB bore scope available on amazon for £46  and is worth every penny (although on second thoughts maybe not, as you will be horrified at the state of some of the bores.)

Thanks for that , ordered one .

However, from what I can gather it will only go down to .20 bore , so will not fit an HMR .

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Had exactly the same with the same rifle & model ,mine turned out to be the synthetic forend was flexing & touching the barrel as it isn’t properly free floating ,& was altering the harmonics depending on how you held it , had the stock shaved out a touch & problem solved .

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R6demon,

 

My finding over the years with HMR. 

 

Sak mods are easily gas cut, the erosion shown on the baffles in the photo i found on my Sak. I swapped for a ASE Utra. 

The dents in the case's-  dont worry about them, they wont cause the issues you have, reloaders have good results with compression dents in them out to ranges that HMR wont even reach, 

Warm barrels  There is a slight chance that you may get some zero shift after continuous round down range but it would normally be consistent, your finding dont seem to be warm barrel issues.   

 

I think your going down the correct route, fault finding in my opinion should be done simple 1st and ONLY 1 change per test, really good scrub and clean, shoot without Mod, check all fixings, swap to different rounds, swap scope. These are all things you can do yourself. 

You could ask a gunsmith to check the crown but i bet you will get charged for a re-crown that probably wasn't needed. 

Forget the bore scope it wont fit and a waste of money, 

The main reason i sold mine was the inconsistent accuracy of the ammunition, i just could not get anything like i had accuracy wise when i 1st bought it nearly 20 years ago. 

What you are finding with your i found with mine. 

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Morning guys, thank you again for all of the responses.  I took the gun into the local shop and he agreed having inspected the rifle that it was more than likely one of the minor issues above, following a brief chat I ended up buying a Tikka T1X MTR at a VERY good price as a replacement and I am now awaiting a weather window to Zero it in!

 

I am disappointed that I didn't get to the bottom of the issue, but I feel that I gave everything a 'good looking at!'

I will be using the same scope / mounts / ammo , so if I experience another issue I can delve deeper!

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NICE BUY, LOVELY RIFLE 😃👍🏻
Good Luck with zeroing it in & doing any shooting you do with it 👍🏻
The ammo you have used with your CZ may not get you good groups.

I would suggest that you buy a box of ammo by different manufactures and fire x5 shots of each type of ammo all on different targets (Once you have managed to zero your scope in roughly) allowing your rifle to cool down after every 5 shots.

Ive always done this with any .17HMR I’ve bought & .22LR  with very surprising results. 
Good Luck with what ever you do 😃👍🏻

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21 minutes ago, R6demon said:

Morning guys, thank you again for all of the responses.  I took the gun into the local shop and he agreed having inspected the rifle that it was more than likely one of the minor issues above, following a brief chat I ended up buying a Tikka T1X MTR at a VERY good price as a replacement and I am now awaiting a weather window to Zero it in!

 

I am disappointed that I didn't get to the bottom of the issue, but I feel that I gave everything a 'good looking at!'

I will be using the same scope / mounts / ammo , so if I experience another issue I can delve deeper!

Luckily you had a spare .17 slot, or this exchange could have been a pain in the rear, having to wait for a variation to remove the CZ and free up the slot again.

Enjoy your new rifle, hopefully you don't have any issues with this one :good:

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17 minutes ago, DR JAMES said:

NICE BUY, LOVELY RIFLE 😃👍🏻
Good Luck with zeroing it in & doing any shooting you do with it 👍🏻
The ammo you have used with your CZ may not get you good groups.

I would suggest that you buy a box of ammo by different manufactures and fire x5 shots of each type of ammo all on different targets (Once you have managed to zero your scope in roughly) allowing your rifle to cool down after every 5 shots.

Ive always done this with any .17HMR I’ve bought & .22LR  with very surprising results. 
Good Luck with what ever you do 😃👍🏻

I have some Hornady, Remington and winchester for this exact purpose!

11 minutes ago, Newbie to this said:

Luckily you had a spare .17 slot, or this exchange could have been a pain in the rear, having to wait for a variation to remove the CZ and free up the slot again.

Enjoy your new rifle, hopefully you don't have any issues with this one :good:

I put my variation in on friday morning and received it back yesterday!  Amazing service by Cambs!

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