Here's the range report from the weekend: all groups shot at 100 yards - the thought being that if it works at 100 yards, 50 yards will be easy to figure out!

IMR 4350: 101.1 grains: 6" group. L + R oriented @ 7 o'clock @ 1 o'clock respectively. There are possibilities with this one. My thought is to try this powder with an increase of 2 grains, then 4 grains. My gut feel / expectation is that as I increase the charge, the barrels will cross before they meet on the horizontal plane.

IMR 4320: 86.1 grains: 12" group. No hope for this one at all, but I had to try a faster powder out of curiosity. L+ R barrel printed at 6 o'clock and 12 o'clock respectively.

RL 19: tried three loads: 104.8 grains; 107.4 grains; 110.4 grains. Groups started 6" apart L + R oriented @ 8 o'clock and 2 o'clock respectively. As the powder charge increased, the groups drew closer and shifted clockwise slightly. This powder seems to have the greatest possibilities of all if I can get enough crammed into the case. The issue I'm having with the Barnes TSX is that it is rather long for weight. I may need to seat out longer that I currently am doing. There was a distinct crushing of powder feeling when I seated the bullet over the 110 grain load. I have ordered a couple of boxes of Woodleighs, so that will also provide more room for play without seating so deeply or going with an overly long OAL.

I am starting slow and working up. The last sound I want to hear is the tinkling sound of bits of Heym raining down all around me lest I create a bad high pressure situation. I don't have the luxury of pressure testing gear at my disposal.

I have read Graeme Wright's book as well as Pierre Van Der Walt's book. The former has educated me as to how groups may shift with different charge weights, and the latter suggests to me that I really need to get the power/velocity up and then hold shots to maximum 75 yards on buffalo. Both books have provided very interesting references for charge weights. Combined with the Barnes reloading manual # 4, I am proceeding cautiously and hopefully somewhat scientifically in a seat of the pants sort of way. As far as when it comes to the hunt, common sense tells me to get close, and then get closer - the game is hunting, not sniping! If I can get over 2000 fps with a reasonable composite group, I'll be content - factory loads are clocking 2050 fps in my gun.

@ Larcher: you are absolutely right! The journey is half the fun. Once it regulates, then I'll need another challenge to frustrate myself with.