how did you determine correct neck tension? How did you measure it?
Well, in post #6 I said:
I'd suggest you just take your dial calipers to the range and chamber and measure a bunch of rounds.
in other words, look for bullet set-back after chambering but before firing.
I have also used a large woodworkers vice and a bathroom scale to compress loaded rounds until the bullet slips. For most rifle calibers it should be around 40-50 pounds with no crimp.
I have measured asphalt sealed & crimped GI ammo at well over 70.
However, my contention is, that much might be needed in a machine gun, but certainly not in a semi-auto sporting rifle.
But the easiest way is just take your expander button out of the sizing die and measure it with your dial calipers.
It needs to be about .0015 to - .002" smaller then bullet diameter in smaller calibers, to as much as .0025" to .003" smaller in big bores, or it will expand the sized case too much to have good neck tension. My .223 expander measures .2225" and works perfectly.
This is assuming your sizing die is sizing the case below bullet dia to start with.
You also use your calipers to measure that before expanding.
Again, I would look for a .222"+ to .223" case mouth before seating a .224" bullet in it.
rc