CZ200S wandering zero, HEEELP!!
Does anybody who owns or owned a CZ 200S experience that although it shoots extremly good groups (PELLETS TOUCHING AT 50 M), the groups move about on the target after filling the tank. Even if I only increase pressure by 20 bar!! This is frustrating to say the least.
I checked the scope by shooting a group, adjusting paralax, zoom etc. the group stays on the same place. I am pretty shure that it is not the Bushnel 6-18 Banner scope.
I am pretty sure it is the front barrel band if it has one.
Remove it and free float the barrel...
The orginal S200 rifles had a free floating barrels and did not have that problem.
Never owned a CZ 200 but ,
I've seen an S400 do this aswell.
The cylinder under a full fill would pull off-centre or twist, then as the air was used the cylinder relaxed and returned to centre.
Is the fill cap / guage not touching the silencer / muzzle break?
You could check that the action is sitting flush in the wood, not off-centre, if it is, then over-tightening the action into the stock can also cause the missalignment I mentioned above.
MOT: Thomson Pneumatic Rifles
I have a number of guys shooting CZ's at the range, they have all had the same problem of zero shifts.
We have tried removing the barrel band and filling and leaving the silencer off.
If the rifle still groups is is more than likely as avion says a problem of tension in the action. The problem would be simple s to solve if it was a problem of erratic shots to start and then good groups, that would be a presure/ speed problem, easy to sort. Find the point (count shots) when the rifle groups and then check pressure, only fill to this presure.
You mite be able to solve this the same way. Sight in and finnish your fill. Refill and then keep shooting without adjusting your scope and see if at some point your groups go back to origional POI.
Also be gentle when removing and replacing the air tube, a faction of a millimeter movement of the barrel could mean inches at 50m
Wow , I'm lucky with mine . Only time I get a zero shift is if I hold the rifle differently & one of my fingers rests on the barrel . It goes wide ! But if the barrel is left alone from 190 down to 120 , I get a good 50 straight shots . Lower than 120 , man it scatters them .
I have greased the thread , tightened all the wood , cleaned the barrel twice , shot 2000 so far .
The gun likes AA field pellets . If I'm farting around at 30 m shooting swingers , I use el cheapo pellets . They dont group worth skwat at 30 m , but great for the 30mm swinger , no problem .
If I shoot paint balls , then its AA field , but kinda boring , one after the other they explode .
Check cylinder allignment 1st
Check barrel grubscrews where fixed into action.
If u have dismantled the stock and reassembled it make sure that the forestock screws have been replaced correctly. Often the forestock front screw seats to deep and pushes the cylinder off line. Measure barrel diameter and measure barrel strap dia. They should not come into contact, strap radius should be 2 100th's oversize. When shooting over a bench, keep cheek pressure on stock light 'cause head is ratehr heavy, if not possible, get different mounts to raise scope. Only once these areas have been checked and found OK, pellet selection, lubrication, and tuning can be attemted
Got the same problem with mine. Thought it might just be screwing the cylinder on and off when refilling, or removing the silencer when doing so (even though I line the silencer up almost 100% when it?s refitted). Checked everything else - except removing the barrel band.
its the barrel banddddddddddddddd.....heheheeeee
I will investigate these and let you guys know...
All the info and reviews I have read on this rifle say that it is supposed to be as good as anything....
Sure hope I can sort this out
I'm sure you'll get it sorted Dirk. May take some time to eliminate certains factors, but it'll come right.
I'm agreeing with you - the flexing is guiding the barrel band. No barrel band and it'll free float.
Now I know sod all about barrel harmonics and I've never owned a free floater - perhaps in the near future though. :P
I took it in to AA in Alrode.
It is not the barrel band....
We found that the front scope mount was monted on the bracket on the barrel and not on the action. This probably was part of the problem as a result of vibrations in the barrel when the shot is fired. This was the first problem
The second problem was that the not so good quality mounts caused me to use shims to align the scope. We remounted the scope with decent mounts.
Without any alterations on the rifle a marked increase in accurasy was observed with no shifts in zero over fillings. Over 23m the shots went precisely through the same hole!.
I will test over 50m before I post my final relpy, as it was not possible to do so today and give feedback. I am rather shure the problem is sorted.
Great stuff Dirk, glad you got it sorted.