How do you guys measure the distance to the lands? I'm using the Hornady inline gauge that uses a modified cartridge case and the bullet of choice. So Mule, you put more "weight" on the primer choice then OAL? Why so? And Antelope, are you going by max OAL from the books or from your particular rifle?
Jaytee I was trying to keep my example simple, but I can certainly provide some additional color.
Just by happenstance, most of my rifles tend to be long throated, so I usually start at magazine length. If the bolt won't comfortable close at magazine length, I uses to seat deeper half turn of the seating step until it does, and call that max. Now I measure with the former stoney points, now hornady case length gauge.
As for primers, I'm a big believer that primers can make a huge difference. My practices tend to mirror Johns. With traditional stick powders I start with a mild standard primer, typically a CCI 200/400, until the case capacity get into the magnum range.
For spherical powders, I always start with either a magnum or benchrest primer. If it's a powder I've worked with, and understand, I may start closer to max as well, since it's they tend to produce their best groups at or near max.
Some of the modern, very fine stick powders can be a little more fickle regarding their primer preference, so I may try both a standard and magnum behind them, or just start with a benchrest primer.
Usually OAL is also the last thing I mess with, unless I'm getting the dreaded "2 in, and one out" at which point I'll start moving it in to see if I can alleviate that specific issue.