Originally Posted by jorvin
i shot a 308 today and with new full sized brass i got 2760 fps. than i shot once fired neck sized brass (same load/bullet) and i got 2675 fps. is this because the new brass is expanding making higher pressures????
If you did not size the new brass before you loaded it, It sounds like there was more neck tension
than on your reloads.
You may want to look at a different expander ball on your dies(Smaller) to get more neck tension.
Also if your chamber is a little larger than the new brass, after you fire form and neck size only
the case has more volume (This will lower the pressure with the same powder charge).
Just a couple of ideas to check out.
J E CUSTOM