CZ .22 Zeroing problems

[wabbitbosher]

Hi there, I’m sure one of you knowledgeable chaps will be able to help me out here

 

My sling broke while out lamping last week

Not really a problem but the rifle dropped off my back and slapped the ground, Soft mud I might add, couldn’t hit a thing from then on, gave up for the night took the it home gave it a right good strip down and clean inside and out,

Off down the farm I go the next day (in the day light) couldn’t get it anywhere near

 

Now I noticed the barrel was touching the stock, took it home again and re-floated it

Back down the farm that weekend, it was zeroing in the form of a diagonal line bullets neatly spread from one corner of the target to the other, my mate the soldier had a go (while saying under his breath YOUR JUST C###) low and behold 45 degree line identical to mine!

The farmers son wanders by and had a go

Guess what 45-degree line

Now if the barrel was bent I’m sure it would still group at 50 yards you'd just have problems at say 40 yards and 65 yards

 

Am I loosing the plot? Could it be a bad batch of bullets?

 

O before you say it we just changed the scope and have the same problem

 

Humph h h h!!

 

Any ideas?

WB

[Harnser]

Hi wabbitbosher ,

Had a very similer thing happen when i dropped my .270 on the garage floor with the scope on .After the fall it shot all over place .So i tried an old tried and tested engineers method of correcting a dropped scope that had scrambled its self inside causing the reticuls to jam them selfs in the scope tube . Try a couple of light taps on the scope tube with a soft hammer . It worked for me . Harnser .

[Dead-Eyed Duck]

Check scope mounts to gun and scope not worked loose. Check all stock screws.

 

If you have changed the scope with the same result, then the only other possibility that I can think of is that if you have a moderator are the bullets clipping it?

 

Don

[Nildes]

Sounds like a scope problem to me. Try fitting a different scope. If you've still got a problem the check stock for a crack around the pillar.

[cubix]

As you are getting the same diagonal set of hits, repeatedly, it implies a predictable problem, the fact that your barrel was no longer floating might also be a clue.

 

The barrel vibrates at its ntaural harmonic, no problem normally as the round will leave the barrel at the same time/point in the vibration cycle each time. As the barrel heats up, all that happns is that the harmonic changes, but the group gets bigger as the change is not that dramatic and firle is built to cope with it.

 

It might be that you are still fouling somewhere - maybe around the action? This would make the normal change in harmonics much more pronounced as the barrel heats.

 

Try checking other fouling areas before hitting your scope with a hammer? perhaps fire a single round every 10-15 minutes to let the barrel cool off between each one and see if they are the same? if the area then fouling not your scope could be the issue.

 

HTH

[Baldrick]

I'm with Cubix on this one, it's likely to be the barrel harmonics. Check everything methodically before tapping the scope. From personal experience, it's also worth dismounting the scope, disassembling the mounts and reassembling the lot. Mounts can shift position.

[wabbitbosher]

As you are getting the same diagonal set of hits, repeatedly, it implies a predictable problem, the fact that your barrel was no longer floating might also be a clue.

 

The barrel vibrates at its ntaural harmonic, no problem normally as the round will leave the barrel at the same time/point in the vibration cycle each time. As the barrel heats up, all that happns is that the harmonic changes, but the group gets bigger as the change is not that dramatic and firle is built to cope with it.

 

It might be that you are still fouling somewhere - maybe around the action? This would make the normal change in harmonics much more pronounced as the barrel heats.

 

Try checking other fouling areas before hitting your scope with a hammer? perhaps fire a single round every 10-15 minutes to let the barrel cool off between each one and see if they are the same? if the area then fouling not your scope could be the issue.

 

HTH

 

 

I'm with Cubix on this one, it's likely to be the barrel harmonics. Check everything methodically before tapping the scope. From personal experience, it's also worth dismounting the scope, disassembling the mounts and reassembling the lot. Mounts can shift position.

 

These sound good to me as i've first tried moving the scope then i borowed a friends scope still with the same problems

Now it did seem to get worse the more we fired it

 

Do you think i should try re floating again ?

[MC]

There is so many things that can cause inaccuracy. Have you tried all of the aboove suggestions?

 

If so, clean the barrel, and I don't mean a quick run through with the rod. I mean a proper back to bare meatl scrub.

 

When you put the action back in the stock did you torque the bolts up witha torque wrench? If so di you use the same setting as before?

 

I would definetely try another scope or at least try remounting your original one.

 

Lastly try a different type or box of ammo.

[cubix]

Try all the scope stuff - maxims razor and all that, but as you say, it does the diagonal even with a diff scope.

 

The only thing that changes when you shoot is barrel temp, and it does so predictably, UIVMM the 'straight line' creep is usually cuased by something touching somewhere it shouldn't. Toughing stops the natural cirular motion of the harmonic, and makes it 'straighter', the gradual increase in temp would move the POI. The figures are something like 1/1000 of an inch variation in harmonic translates to one inch at 100 yds. It doesnt take much. But like I said, normally the bullet leaves at the same point in the motion each time so its not normally an issue.

 

Imagine moving a penicl around the inside of a can, then stuff something else in there - the circular motion becomes a segment.

 

I think the whole trigger assembly etc shoud not touch the body at all exept for a couple of points at the bottom. Clearly you originally gave it a hefty whack to knock the barrel out of alignment, best the check other clerances as well.

 

If you're stuck I can look up the details of where else it should/should not touch.

 

Perhaps I'm talking out my xxxx no doubt others will know more than me!

[cubix]

Do you think i should try re floating again ?

 

Sorry, didnt read your post properly.

 

If you refloated once, then the barrel is fine - the interference will be further back. Of course, once you find that (if its there at all) and fix it, your original re-float might need to be done again?

 

 

I'll be fascinated to hear what you find the problem and solution to be.

 

Cubix

[pin]

If the stock has been off for cleaning could it not just be overtight or undertight action screws?

[markbivvy]

If the stock has been off for cleaning could it not just be overtight or undertight action screws?

 

the action screws can cause all the trouble you discribe if they are to tight.

if it shot right before the drop , floating the barrel or freeing the action wont be the problem.

[rabbithunter]

What about sticking the gun in a vice and bore sight it and see if you can hit the same place on a target say 20 yards

[deadeye ive]

To summerise

.22 lr rifle

dropped in soft mud

now shoots diagonally no matter who's shooting

Same with a different scope

refloated barrel

fully cleaned rifling

STILL shoot diagonally consistantly

 

Something is loose

I'm guessing you have a moderator like a sak or parker hale .IF SO have you tried without this attached .Has they are mass produced items the thread fits are very poor and normally all contact is taken up with the last turn which don't leave much margine for error .Also the material removed for such a moderator is quite excessive and if lets say the Mod hit the ground first no matter how soft then this could strectch the material at it's weakest point (machined area behind the threads)and not visible to the naked eye ..DTI and lathe would confirm though .

 

Any damage to a rifle barrel would,nt give consistant grouping due to heat no matter how mineute

 

I can't think of anything else.

[wabbitbosher]

To summerise

.22 lr rifle

dropped in soft mud

now shoots diagonally no matter who's shooting

Same with a different scope

refloated barrel

fully cleaned rifling

STILL shoot diagonally consistantly

 

Something is loose

I'm guessing you have a moderator like a sak or parker hale .IF SO have you tried without this attached .Has they are mass produced items the thread fits are very poor and normally all contact is taken up with the last turn which don't leave much margine for error .Also the material removed for such a moderator is quite excessive and if lets say the Mod hit the ground first no matter how soft then this could strectch the material at it's weakest point (machined area behind the threads)and not visible to the naked eye ..DTI and lathe would confirm though .

 

Any damage to a rifle barrel would,nt give consistant grouping due to heat no matter how mineute

 

I can't think of anything else.

 

 

Have you got a mod on it? i had the same problem with my cz with a parker hail mod the baffels which are loose had moved inside and the bullets were clipping them as they were out of line a kwik trip to clarkies a new set of baffels £6 job done

 

I've tried it without the mod, thing is as soon as the zeroing went funny removing the mod was my first port of call because i could do it in the field

 

WB

[Down South]

My mate has a 10/22 that started doing something similar. Out of desperation he retightened everything and found the tiniest bit of slack in the barrel clamp. After tightening that the gun was true again. I'm not familiar with your rifle but it's worth checking.

[A Sick Old Man]

I have had this same pattern on a .308 rifle, it was the scope creeping up the rifle.

 

I had a mare of a time with my 10/22 tried eveything and what cured it was floting the barrel, if the MPI moves during constant firing I would say the barrel is kissing the woodwork somewhere.

[deadeye ive]

I've tried it without the mod, thing is as soon as the zeroing went funny removing the mod was my first port of call because i could do it in the field

 

WB

And the results were still diagonal grouping

[wabbitbosher]

PRESTO !!!

 

When i first removed the mod the scope was bent , so changing the scope didnt fix it because <<<<<<<<<<

 

 

Wait for it

 

 

 

 

 

 

 

 

The bloomin mod was slightly bent as well

 

T Grimbley of Corby spotted it in the end

Best of all he didnt charge me a penny !!!!!!!!

 

Dam fine chap

 

Alls well that ends well

 

WB

[cubix]

Occam's razor !

[wabbitbosher]

Occam's razor !

 

? ? ?

 

[charadam]

Pretty sure the gentleman means not Maxim's razor as quoted a few posts above, but Occam's razor.

 

Usually expressed as the theory that "All other things being equal, the simplest solution is the best."

[cubix]

Who me?? Not me guv.

 

On the principle that people who try to sound clever and get it wrong end up looking stupid (which I do from time to time) I might point out that Occam's razor is what I said.

 

However, I was wrong in the respect that the correct spelling is 'Ockham's' but it usually gets Occam's [sic], which is my usual version .

 

It is however also known as Occams' Maxim.

 

I do, for instance, despite my best efforts, call 'Art Garfunkel', 'Simon Garfunkel'. But I can't recall ever doing 'Maxim's Razor' - now that would be embarrassing in company. Perhaps I have though, and they were too polite to tell me.

[cubix]

Perhaps Maxim's Razor was 'Firing as many bullets as fast as you can is good.' ?

[wabbitbosher]

you dont want to go using "Maxim's Razor" you might catch sommat Nashty ! "Init"

 

All's Swell that endeth Welleth

 

Innit Eth