factory rounds

[Squirrel_Basher 17,102]

I use a .222 very regular and clean it every 10 shots.The last batch of bullets bought were my usual Federal 50grain but the zero at 100yds has moved up 30mm.This change is consistant with 15 shots fired .The scope has not been knocked to my knowledge.Is there that much fluctuation in factory loads.

p.s I buy 300 at a time so maybe somethings changed at the factory .Anybody else had this with Federal.