Re: Quick Question.
RT2506's method is what I use, but no one has mentioned magazine length!
If you find that the COL is too long for your magazine, and you don't want to single load each round, you'll have to work at max magazine length and work backwards to find the 'sweet spot'. This is how I do it for my hunting rifles, target/long range rifles are different.
There is another method that works easily.
Place the bullet you're going to use in the chamber, holding it in place with a 'Bic' pen or similar, carefully slide a cleaning rod with a flat end through the muzzle, until it contacts the bullet tip, mark with pointy marker flush with muzzle, remove rod and bullet.
Place the bolt back in and slide the rod down until it touches the bolt face, mark again flush, remove rod and measure the distance between the 2 marks.
This is the COL into the lands for that bullet, you can then work back from this in .005" increments until you find the 'sweet spot', but again, if this COL is longer than your magazine, you'll have to seat to that COL and work backwards.
Unfortunately, today's rifles seem to be long throated from practically every manufacturer, so a lot of rifles will never be able to have the bullet seated close to the lands due to magazine length restrictions, unless single loading is used.