Buffbob,
Thats true, i may have opened up the collet holder years ago and dont remember. I remove the spring clip from the cutter shaft, it makes it easier to get the long shells into the collet-trimmer body, that way you don't need an extra long trimmer. If my poor memory serves me, i bought it in 1975.
I dont do any neck turning on the 338-408 cases. I tried it and didnt see any difference in group sizes. If one has a tight necked rifle then sure. With the different brands of 408 brass, you might see some with thicker necks. When the 375-408 brass comes available, necking down will become a breeze! Just run them through your sizer die, one step.
Dave