I have always preferred loading within .005 of the lands, but some of my guns will not let me seat the bullets this close due to magazine limitations. Some of them are less finicky than others about seating depth. My 308 just plain shoots and seating depth has not been a major factor. Long throat and I seat Hornady 168 gr. AMAX's about .140 off the lands due to the magazine. My Remington 700 338 WM wants 225 gr. AB's very close (<.005) to the lands.
For the best accuracy, always use a bullet comparator which measures to the ogive, not the bullet tip. Lead tip bullets will have the most variance in OAL, but all bullets (tipped, hollow point, etc,) will have some variance.
For a good tutorial on seating depth, read the Berger Bullets manual. Try 4 different loads which are adjusted by .030 between each load. One of these should show more accuracy than the others. You can fine tune your seating depth up or down in smaller increments from this preferred seating depth.
Trying to find the best seating depth by making very small (.002) adjustments can be an exercise in futility. If you measure the ogive on many of the bullets you will variations equal or greater than this amount. I tried Nosler LRAB's and found variances up to .008 when I measured about 20 of them.
Good advice right there.i watched a guy on YouTube get his coal for a bolt action rifles. He first slightly seated a bullet in a dud case. Then he chambered the round and the bullet seated it's self to the maximum coal.
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When placing a dummy round [bullet seated long in an empty case] in the chamber to find the lands , use a fired case or wallow out the neck of a new case a tiny bit . So that the bullet will contact the land and slide into the case showing exactly where the Ogive of the bullet touchs the rifling . Problem is getting the round out of the chamber without the bullet moving , when you get movement your results are no good .
I've did it five times and came up w/a different measurement each time -irritating to say the least .
SO put a dab on elmers glue on the dummy round bullet/case slide it into the chamber - give it 15 minutes to dry -remove the dummy round -now you can measure without worring that the bullet moved in the case mouth . I use a Sinclair bullet comparator , measuring off the bullet tip can be several thousandth off as already stated .
I move out 15K increments myself and never more than 10K into the lands .
Good old elmers glue ....
