Just to add to your confusion, I do not full length resize any of the cases I currently load for, but I do more than just neck size. I use full length sizing dies, but set the die so that it does not touch the shoulder of the fired cartridge, but resizes most of the neck, and body. In a straight walled case this I simply re-size enough to have good neck tension, but with low and medium pressure bottle necked cartridges (ie .22 K-Hornet, 30-30, etc) that are supposed to head space on the rim, this allows a second point of contact that can be used to set up what I call a dual head spaced round (works only in the gun the round is fired in) For the guns I have tried this in about half of them shoot better, and the other half do not shoot as well.