can any-one advise me please. I have a New CZ 452 Thumbhole Stock .17HMR. Basicly it wont hold Zero????? To-day again, i checked Barrel clearance, mot cleaned it, have cleaned it. So i get it to 5 shot clover-leaf Great, have a look about for a live Quarry shot, miss miss back to a Target an the Rifle spray's again. To- day i tried four Different type's of ammo an get the same result. So off come's the Mod and as good as one hole 10 shot group. Result or so i think shot a crow 2 Rabbit's back to missing. So i check now i am back to spraying. I dont know what to do NOW "HELP PLEASE"