I have very good accuracy with H322. My load is 52gr H322, Hornady 265 FlatNose, Fed 210M in an R-P case - 2217 fps with an SD of 7, Accuracy about MOA, killed a 6 point bull with it at about 55 yards. I didn't care for the way the 265 broke up, good for deer though.
I have used 47 gr H322 under Speer 300gr for 2002 with SD of 6 and MOA at 100 yards.Haven't shot anything with the Speer 300 gr (discontinued?). I have also used Leadheads 265 gr Cast GC bullet with excellent accuracy with full power loading.