01-02-2021, 07:05 PM
Bob, mine are just lead soft tips. They probably have the BC of a pregnant sow, but they are serving their purpose. I use them for fireforming both 6.5 G and 7.62x39 brass. It's not obvious with most factory brass, but it is something that *should* be done with virgin brass since it comes from the factory at minimum spec while a die won't take it back down that far during resizing. So the virgin and fried/resized cases will have different volumes and while load development with virgin brass will get someone in the ballpark, results won't normally be repeatable at the same charge level. My 6.5 Creedmoor had a 50 fps difference between virgin Starline and fired, holding all other variables the same (the fired is/was faster). Necking brass down helped me visualize the difference and I've fireformed all virgin brass since. Do you have a slight bulge at the shoulder body junction on what you've sized down? It's hard to see with my nickel brass above, but since brass flows down during necking down, the die pushes brass below the shoulder and it goes outward to the sides of the die that work on the case body wall. So the distance between that ring and your case body is the minimum extra amount that the body will expand on its first firing vs subsequent firings.