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iv also had a different situation where the recticle inside the scope came loose so give things a good shake to see if anything is loose

most of the time its just loose bolts or screws

https://www.nzhuntingandshooting.co.nz/f15/dum-86976/

all the obvious causes listed in here just incase its a hidden obvious cause

when this happened to a friend with his 7x57 it came down to switching primers or picking up the wrong type for the load

if the others were all on target this isnt very likely tho

is your dial a zero stop?