How much neck tension do you figure? You want accuracy? Try IMR 4350 55 grs.
That's good to know. Thanks for the insight. That seems to agree with what others have posted on this thread thus far. It might take me a week or two to get out to the range again to test this, but when I do I will update this thread with my results.New cases vs Once fired? I learned almost the hard way. Fire form new cases first with a lower charge. THEN start your load work-up. I had as much as 1 gn lower difference in my 270 when I started seeing pressure signs. I'm almost sure what you experienced was pressure change.
Have you measured case capacity of new vs once fired brass? Could be some changes going on there, and you might need to adjust charge weight accordingly
I could use some help with my load work up for my Sako A-7 Roughtech chambered in .270 winchester. When I handload brand new Hornady brass, it shoots 3/4 inch groups and I am very satisfied. However, when I reload that exact same brass after it has been once-fired, groups open up to about 1.5 inches. What's going on?
I am using a bunch of brand new, unfired bulk Hornady brass, 130 grain Sierra Game King bullets, and 61.6 grains of H4831 powder. I am also using a Redding full length bushing die with a .302 bushing. I take the new brass and run the expander ball down the mouth in order to uniform it. Then, I remove the expander ball and full length size the new brass with a .302 neck bushing. (this does very little sizing on any of the brass, but I still feel like helps to keep things uniform.) I then load it and seat the bullet with a Lee seating die. Take it to the range, and get great results. Then I take the brass home, tumble it, lube it, and FL resize it with the same neck bushing, but using no expander ball at all. (I rely on the boat tail bullet to do the expanding when the bullet is seated). I load it with the same load, take it to the range, and it shoots like crap. Do you have any idea what is causing the inconsistency between the first and second loadings/firings of this brass?