I use H4831 for the 100 gr bullet in a rem classic 243.Works wonders using a rem 100 gr core-loc.
First off I got this load out of an older reloading manuel that gave 46 grs as max,I check a up to date hodgens manuel and they have dropped it down to 42 gr max. So if you try it be sure and work up.
Tried this load in 4 different rifles and it shot well below an inch @100 yds. in all 4,one was a tinka,rem classic and rem adl and a savage
The savage I didn't know the fellow he was at the range and shooting factory rounds so I let him shoot a 3 shot group and he put 2 in the same hole and one 1/2 inch to the right.Shot several one hole groups with the tinka and my rem classic,even one group at 300 with the classic that measured 1/2 in.Only shot 2 groups with the adl and both were less than an inch.
Now there is one draw back with this load it only shot the small groups using the rem core-loc,tried
speer and seirra and they shot well but not the tiny groups like the rem.The top group is with a sierra 85 gr bthp and the bottom group is the 100 core-loc.

Anybody try BLC-2 with a 100 grain bullet?

I used H380 and IMR4350 when I had a .243

I use RL-19 for my 243 win and IMR 4831 in my 30-06 . IfI load for a semi autoI use IMR 4064 0r 4895

I think you might find that a slightly fast powder for that application. I'd recommend against it.

I would try both IMR 4064 and IMR 4350; both are excellent powders in the .243. My pet load is 40.5 gr of 4350 behind a Hornady 100 gr SP. That load has accounted for a lot of whitetails and a few groundhogs.

IMR 4895 with 95 grain noslers is working for me. And the starting loads are more accurate than the max loads, best results have come with 31.5 grs and 32 grs. Bugholes