Kurtz,
After I sent my post I flashed that I had seen load similar data on:
http://reloadersnest.com/frontpage.asp?CaliberID=135
to what you gave in your original post above. Then I remembered that those loads are yours.
I did some interesting experiments this weekend as well. I have a 20-inch 1:10 twist AR15 barrel on loan so I re-shot all on my 155 grs Palma loads from a 16-inch barrel posted on:
http://reloadersnest.com/frontpage.asp?CaliberID=135
By the way the "loaner" barrel shoots VERY VERY WELL!
One more set of experiments this weekend and I will get it back to the owner.
(Thanks RR.)
Adding 4-inches of barrels adds anywhere from 60 to 80 fps. Also seating the bullets about 0.05-inch deeper into the case adds about 50 fps but also seems to rise the pressures as well. It seems that there is a "sweet spot" as far as bullet seating depth and pressures/velocities go... too far out touching the rifling and the pressures will go up and too far into the case and the pressures will go up. The actual position of this "sweet spot" is dependent on the throat/freebore of the chamber. This is how Roy Wheatherby got the high velocities our of his rifles.
It is always fun to learn new things
320pf