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CZ452 Style .22LR Won't group at all


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On 05/06/2021 at 18:09, Dave-G said:

If it were mine and I'd got decisively desperate enough to scrap it (not saying you have reached that stage yet) I'd risk a tickle with a 6mm fine tapered file or reamer into the end with some tape over the smaller diameter before scrapping it - and maybe a ball stone too.

You can get brass muzzle crown lapping tools online for a few quid, quick run in a drill with some lapping paste and it might tidy it up a bit. Or you could give it the Larry Potterfield treatment with a round brass screw and lapping compound. Both methods have the inherent risks of making a pigs ear of it though so user beware!

Might be an idea to give the barrel the scrubbing it so desperately needs then pull a bullet and slowly push it up the barrel with a cleaning rod then check for rifling marks and for galling marks caused by a bad crown.

Aside from dropping a rifle or corrosion I would bet the other leading cause of a damaged crown is people being too rough cleaning the barrel, running a rod down from the muzzle or overshooting with the rod and dragging it back hard through the muzzle.

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36 minutes ago, Rob85 said:

You can get brass muzzle crown lapping tools online for a few quid, quick run in a drill with some lapping paste and it might tidy it up a bit. Or you could give it the Larry Potterfield treatment with a round brass screw and lapping compound. Both methods have the inherent risks of making a pigs ear of it though so user beware!

Might be an idea to give the barrel the scrubbing it so desperately needs then pull a bullet and slowly push it up the barrel with a cleaning rod then check for rifling marks and for galling marks caused by a bad crown.

Aside from dropping a rifle or corrosion I would bet the other leading cause of a damaged crown is people being too rough cleaning the barrel, running a rod down from the muzzle or overshooting with the rod and dragging it back hard through the muzzle.

googled - thanks 

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37 minutes ago, Rob85 said:

If my missus didn't have the financial eyes of a hawk I would own all manner of seldom used tools 🤣

I'm lucky my other half tells me to do what I effinwell like 'cos I will anyway. :-) I dn't need one of those though.

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1 hour ago, Rob85 said:

You can get brass muzzle crown lapping tools online for a few quid, quick run in a drill with some lapping paste and it might tidy it up a bit. Or you could give it the Larry Potterfield treatment with a round brass screw and lapping compound. Both methods have the inherent risks of making a pigs ear of it though so user beware!

Might be an idea to give the barrel the scrubbing it so desperately needs then pull a bullet and slowly push it up the barrel with a cleaning rod then check for rifling marks and for galling marks caused by a bad crown.

Aside from dropping a rifle or corrosion I would bet the other leading cause of a damaged crown is people being too rough cleaning the barrel, running a rod down from the muzzle or overshooting with the rod and dragging it back hard through the muzzle.

I think this is about it.  Invest in a re crowning tool as above and then check the zero/group without the silencer because it maybe the threading was as badly done as the crowning or whoever threaded it boogered up the crown in the process. I have never known a 22RF get shot out and have a friend who has just purchased an old Brno and I mean old and that is a tack driver having had many hundreds of rounds through it.  The Hawk scope is a good choice and very doubtful that is the problem.

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On 05/06/2021 at 18:09, Dave-G said:

If it were mine and I'd got decisively desperate enough to scrap it (not saying you have reached that stage yet) I'd risk a tickle with a 6mm fine tapered file or reamer into the end with some tape over the smaller diameter before scrapping it - and maybe a ball stone too.

Hi everyone, thanks for all your responses.
 

So after reading your comments, I've done the following:

1) Check the fit of the barrel The note catches quite some way in front of the forward mounting point.. Youtube video here 

 

 

 

 

 

2) Remove action from the stock. There's clearly some rubbing happening here (see photos).

3) Clean the crown with some bore cleaner and tissue. I think the photos are making it look worse than it actually is (a couple more photos included).

4) Had a great phone call with @Saltings he's described how to temporarily bed the rifle to float the barrel. Unfortunately as I completed this, the heavens opened and I haven't got to try it out yet.

5) Re-mounted the Hawke skope for testing.

Todo

Give the barrel a damn good clean.

Test fire - with and without moderator. Not too worried about the neighbours for a 3 shot string :)

Go to the local gun shop and pick up some eley subs

Will keep you updated.

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The problem with the barrel catching could be a dodgy fiver , send me it and ill check it out 😂👍 , i would also try some rws subs as there have been a few issues with eley accuracy of late

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5 minutes ago, telf said:

The problem with the barrel catching could be a dodgy fiver , send me it and ill check it out 😂👍 , i would also try some rws subs as there have been a few issues with eley accuracy of late

:D I'm glad I didn't use a tenner, could have got expensive if I need to send them for testing.

I'll try and hunt some RWS down too!

Cheers,

Harv

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  • 3 weeks later...
On 06/06/2021 at 21:03, Dave-G said:

googled - thanks 

I have had good results re-crowning using a suitable large round head brass slotted screw and some lapping compound - save buying a single use tool

You can do a temporary "bedding" job using shims cut from old soft drink cans - it will allow you to get the action & barrel out of the stock, to see if contact in that area is one of the variables that are the cause of the problems

Edited by saddler
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On 05/06/2021 at 18:09, Dave-G said:

If it were mine and I'd got decisively desperate enough to scrap it (not saying you have reached that stage yet) I'd risk a tickle with a 6mm fine tapered file or reamer into the end with some tape over the smaller diameter before scrapping it - and maybe a ball stone too.

Won't need scrapped, if the crown's gone just a cut and rethread.

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  • 2 weeks later...

Hi everyone, sorry, it's been a while, and I've been busy with work and not had much time for looking at the .22.

I called round a few gun shops locally to see if anyone had a gunsmith who could re-crown it. The closest suggestion was Birmingham, about an hour or so away.

I followed Saltings advice from on here and shimmed the front of the action a little to float the barrel, and the groupings improved. I also bought some Eley Subs, to try, which helped rule out the ammo.

The last few evenings I've spent a little time sanding out the stock to float the barrel without the shims.

The floating of the barrel ha1163570657_NewGrouping.png.2a4bdb304a0ac9ccfda6c61b22ca9630.pngs made an enormous difference- see the photo below. The flyer is down to me, and not the gun - this is at 40 yards.

Since taking this, I've sanded a little more out, and tried it with the original Winchester ammo - both are grouping really well.

What I have noticed is that the plastic stock has a little flex in it. It's not difficult to bend it to touch the barrel again, I think the nasty bipod I had on it could have been putting a different amount of pressure on the barrel each time from the stock.

I'm now keeping an eye out for a new/second hand stock to go on it, thinking about a new, proper bipod, and maybe even fully bedding it to give a little more clearance.

Thanks again everyone, really glad for not giving up on the gun.

I'll update if I do more to it.

Harv

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On 12/07/2021 at 11:06, telf said:

Couple of pics of it 

F008B6AC-4E3C-4A57-8A80-825A6B28A8BE.png

8EC49BE8-9A89-417C-8B8D-836135082F94.jpeg

This looks lovely, it would be a shame for me to butcher it - a little looking online seems to show I'd need to make quite a few changes:-

 

There's a great thread here which has loads of pics. https://www.rimfirecentral.com/forums/showthread.php?t=344852

In the end I've got in touch with Parmoor gun stocks and bought an unfinished stock for £170 delivered.

https://gun-stocks.co.uk/

If anyone is interested, I'll continue the thread with what difference this makes.

 

Harv

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