Most serious target rifles will group to 1/4 to 1/3 a MOA elevation (forget wind that's more down to personal ability!) & not many people can equal that, so your shooting system accuracy is dependent on your gun, your group ability + the deviation of the ammo & for TR I get abt 1/2 MOA just lobbing the stuff in without fiddling with micro-scales & all that.
Just keep the thrower 3/4 full so the pressure on the feed hopper is constant (ish).
Better off weighing the bullet heads & screening them me thinks as I used to do with .22
Don't get anal about weighing, get anal about breathing, hold & trigger control instead. After all the most accurate rifle & ammo & sights in the hands of a non shooter isn't going to do better than a decent shot with a decent rifle & ammo mix.
StevE - go for it dude 
:lol: :lol: