Problems with Autofill

I’m trying to auto fill to the bottom row of my spreadsheet with the code:

Sub Step1()
   Dim LR As Long
   LR = Range("O1:P1").End(xlDown).Row
   Range("Q2:AJ2").Select
   Application.CutCopyMode = False
   Selection.AutoFill Destination:=Range("Q2:AJ2" & LR) 
End Sub

However it always fills a few hundred rows lower, but I can’t work out why!! Any ideas please?

Thanks