Speaking generally when using bushing dies of any make - you don’t need to neck turn if the die has an expander button or you use a separate expander mandrel. The use of the correct diameter bushing coupled with an expander mandrel (to open the neck 0.001” or so) will uniform the internal diameter even if there’s the normal slight variance in neck wall thickness from case to case.The comp die does not decap, and you need a smaller bush.
If your using the comp die to resize your necks you really must stick to 1 one batch of brass AND neck turn, using a mixture of brass with difference in brass thickness will only create problems and definitely inconsistent neck tension negating the reason totally for using these dies, you may as well use standard RCBS dies.
And then of course regular annealing.
Using a bushing die in conjunction with an expander mandrel allows for minimal working of the neck coupled with uniform internal neck diameter.
Neck turning would be required only if there’s no usage of an expander button or mandrel.
