I am working up varmint loads for my 25-06 and find myself seating light bullets (75 V-MAX) way out to meet the lands-- so far that I wonder if they are safe. How deep does the bullet need to be seated, realistically?

MOA, you can safely seat bullets to touch the lands, but you have to be wary of pressure. The safest bet would be to stay well clear of max loads with such a seating depth.

Seating the bullets to touch the lands aids in starting the bullet straight down the bore - which is why many precision shooters choose this option. Drawback: if you ever need to extract an unfired round, you may find that the bullet is stuck in the barrel, and you end up with a magazine full of powder. Not advisable for a hunting rifle!

Best actual seating depth seems to be a function of gun and bullet - i.e. no hard rule for what is best.

- mike

I interpreted the question as regarding the depth of the bullet within the case.

It is commonly recommended that one calibre of bullet grip, e.g., .257" for the 25-06, be achieved.

I have used as little as .125" grip on the short 25 calibre bullets with no problem but my rifle is converted to single feed. I don't know if such minimal grip would be OK in a conventional magazine.

I neck size with a collet die and my velocities are quite consistent.

Another consideration when working with a long throat would be using a Sinclair chamber length gauge to see if you can leave your brass a bit longer than SAAMI specs. Many factory chambers are generous and this could give you a little more grip on those short bullets.

Regards,

As said, the one caliber rule gives a save grip and there will not be troubles with magazines, when hunting or match shooting or by rough transportation.
You may loose a bit of precision due to bad alignment of the bullet, yet.

I like to set the bullet far out because I check the bullet concentricity with a gauge after bullet seating: it is very easy to correct its alignment.
The cartridge should be stored carefully as having the alignment destroyed whilst transportation is highly unwanted :-).

This is the opinion of a single shot paper puncher.