I found an HX serial # 30-06 at a pawn shop a month or so ago. It was absolutely like new, didn't even have any marks on the scope base that the rings normally leave behind. I may be wrong, but I don't think it had ever been fired. I got it for $160 out the door!
Anyway, on to the point of this post. I have been shooting some SMP IMR-4895 with Winchester 150 grain power points in LC military cases. None of my groups have been great, about 2" @ 100 yards is about as good as these loads have produced.
I loaded 3 rounds with IMR-4831 and Hornady 178 grain A-Max bullets and loaded three more with 1 more grain of powder.
The first 3 shots with the A-Max's measured 1" @ 100 yards!

I then shot the next load of A-Max's with 1 more grain of powder, these three shots measured just a hair over half an inch!

I was absolutely tickled to death!
I went back to the house and loaded 7 more rounds of that load, that was all the brass that I had sized and primed. I then gave my barrel a really good cleaning because I hadn't cleaned it for several rounds. It was really dirty so I soaked it and got it ready for the next day.
Back to my bench the following day with THE load for my '06. I was very, very dissapointed. The load that shot right at .5" the day before was now 2 to 3".
Do you think cleaning the barrel may have caused this?
I'm going to run some more rounds through it and if it come back in I don't think I'll clean it again until it starts shooting bad again.
What do you all think!
GOOD SHOOTING!
Slufoot