Question about seating bullets near or touching lands

[MadDog]

I am going to try a few more things to try to get acceptable accuracy out of my upper. One thing I want to try is to seat some 240gr SMKs near or touching the lands. My barrel has a very long throat and I will not be able to use mags for this experiment. I really just want to see if it makes any difference.

My question is how will this change pressures and velocities from my previous loads? Should I start with a lower load even if I am only loading subsonics? Where would you start relitive to loads that were running around 1000fps?

Also, what have you found to be an optimal distance from lands for accuracy with subsonic loads?

Thanks,

Joe