My long lee is super accurate with handloaded ammo. More accurate then it should be.
I use Sierra pro hunter bullets and a starting charge of 4895 or varget (usually 36.5 to 38 grains iirc) . Loads are right around 2000 fps and like I said accuracy at 300 yards is VERY VERY good.
For cast I use a 185 grain lee bullet sized to .312" with 18 grains of 2400, or 13.5 grains of red dot. Same as above great accuracy.