I just got a new barrel put on my 243 and I am looking for powder recommendations for shooting 90 grain bullets. I have used 7828 and 4350 in the past but I have not researched any new loads in over 10 years.
Using a straight 243 but h1000 is a good choice. It'll extend your barrel life considerably with decent accuracy and SD's. Start at 46 and go to 49 or until you get too much crunch. It's doubtful you'll overpressure. At 47gr, 26"tube and 112gr match burner I'm around 3050
H4831 h 4350 Imr 4350 reloader 26 h1000 rl16
My fire form load using Lapua brass federal 210 primers Imr 4350 41grains using 105's shoots under half moa five shot groups. Sd13 for 20 shots. 20" pipe just under 3k fps