for something to try, i loaded up some 180g Hornady btsp's at one time. i used reloder 15, up to 31 grains. none showed excessive pressures, but 31 was getting there. the primers progressively grew a larger flat spot (less rounded on the edges). i am not sure how much further you could go with them. on those bullets, an oal of 2.785 worked in my Marlin 30A 30-30. none of them were crimped, i do not remember if the canalure was pushed inside the neck or not (it was 3 years ago). i had to look back thru the load data to find these. i would suggest using a slower powder if you have something listed in the lee data (or the page listed above, thanks Steve C.). the lee manual was the only place i could find as well. i have used IMR 4831 in my 30-30 on several occasions, with no ill results. the velocities were not great, but it did work. at that time i did not have a chronograph, but the point of impact was at the highest point 6" lower than where the scope was sighted (170g bullets @ 100 yards), being the drag coefficient was so much higher on the 180g btsp's, it would lead me to believe that most of the drop was due to reduced velocities, rather than the extra 10 grains of bullet weight. i have not tried any further experiments with heavier bullets since that point. but i wish you all the luck in the world. may i ask if you have a particular purpose that you need a heavier bullet for? or is this for the sake of knowledge?