Different lot numbers of the same powder can, especially if you are using dippers or bushings, or you didn't hold your mouth right the last time you weighed a charge.Still, can the noticeable difference I have obtained in POI and group size, between shooting W-231 and HP-38, everything else remaining equal (bullet, brass, primer, seating depth, crimp, even same gun) be caused just by minute individual variations in the componets ?
Plus, there is the human factor. None of us can shoot the same great group over and over.
I see where folks post several pics where they shot one group with each load and say this was best and that was worst.
Unless they are very, very, very good, one group means little to nothing.
On a bad day I can shoot a gosh awful group with a great gun/load no problem at all. On a good day I can make that same gun/load look like a million bucks. On a so so day I can shoot a great one and then a horrid one back to back groups. :banghead:
Most days I can tell if the gun/load is trying to shoot and I am just holding it back, but there are times when I am not sure and have to come back a different day and retest.
Load testing can be aggrevating some times, but very rewarding at other times.