Some times you just have to look awhile. I never started with a bullet, just picked 4 or 5 that were readily available, a couple of powders, started at the middle of the powder range for baseline, picked out 1 or 2 that grouped the best. Then I load up 1 or 1.5 grains increase, if the groups shrink, I go on up, if they enlarge I go back and drop the same and try it. The worst shooter I have so far is a 280 that stays around 3.5 to 4" at my 200 yard range, nothing to write home about, but usable on deer size game, I am now going to try varying seating depth, sorting cases, and another powder before I decide to give up the effort. I also try to find one load for each rifle and then just match that load up with the usage. Over the years I have shot up 10-15 times as many rounds in load development as I ever fired in practice and hunting together. I usually shoot 3 rounds from the deer guns in the fall to check the zero and foul the barrel, and one at a deer. Don't give up yet, if you get through a couple boxes of bullets and a pound or so of powder with no improvement think about it then. Best of luck.