Jammed/Jumped/Into the lands

[moonsign]

I'm using all of Bergers Target match bullets, in my .243/8 twist barrel, and a term excapes me. I use a Horny AOL guage to check seating depths of each grain of bullet, against the lands.
I understand jumped, and jammed, but I see where people say 'Bergers like to be seated well into the lands'. I'm having a problem understandin that, and how do I check the seating [well into the lands]. So far I AOL the bullets, then back off
ten thousants. Have'nt seating aginst just yet.
couls someone enlighten me on this? Thanks 'Moon'

 

[js223]

Is the tool the one where you put a modified case on it that
has a slip-fit for the bullet, move the bullet to the lands
with the rod on back and lock the rod at that point?
If so, you use the tool to find where land contact is for a given projectile. That is your 'at the lands' measurement. If you seat the bullet shorter, then you are 'jumping'. If you used a longer OAL than your contact number, then you are 'into the lands' also known as 'jammed'.

 

[tenring]

To check seating on the lands, I start with a device that will show light contact,Hornady comparator is OK). With calipers, write that measurement down. Then seat the bullet you are using into a sized case to the same length. With 0000 steel wool, clean the bullet or color it with a magic marker. Chamber it and look closely at the bullet,use a jewelers loop if you have one) for contact marks made by the lands. If they are non existent or very light, pull bullet and reseat it .005' longer. Do this until contact is obvious. This is your zero OAL. From there seat bullets longer or shorter until you find a suitable OAL. Caution - seating too far into the lands can increase pressures especially with maximum loads.