If it's been fired through the same rifle your going to shoot it from, then you can certainly just neck size until it needs bumping, which it eventually will. I recommend chamber checking each piece after necking it, and prior to going forward with priming, charging, and seating though, just in case you get an odd ball piece that may have already been tight from the get go, I run into that now and then, in fact I just did about an hour ago. But I also have a very tight chamber, which I'm sure has some bearing on this.
I get 2-3 more cycles off my brass by necking my 7 mag. brass, which is to say 10-12 loads by necking it v.s. 8-10-ish only FL sizing. But because I load on the rather warm side, I run into problems with the web getting pushed out before my primer pockets get loose or incipient head separation presents. This is something I'm going to address with a Innovative Technology collet die in the very near future.
As for primers, the powders and data I load with are published with magnum primers, so that's what I've always used. In other words, stick to the published recommendation in this respect and you'll be fine.
GS