I have been looking for ways to shrink my groups with all my rifles and have started looking at expander mandrel as another part of my reloading process. I am not into bench rest or any competition shooting, but would like to shrink my groups and my ES/SD. I have shopped around and was set on getting a Sinclair Gen II, but they are not in stock, so looking at 21st Century now since they are in stock, plus they seem to have it broken down into .0005 increments. Since this will be for hunting rifles, how light of neck tension should be used, again I am new to using expanders. My current setup is using FL Sizing die with the expander button, it measures at .260 on the calipers for my 6.5 Creed, my groups range from 1.0 to .595 in size, should I use .263, .262 or .2625, will it set it to this or will spring back in the brass cause it to be smaller than size on expander? Again I am new to using expanders, just FL size with standard expander in die and seat bullet, using expanders, would it change anything for group's or ES/SD or am I just p#### my money away??