I also have a .243 Win. H&R Ultra 24" fluted bull with Choate stock that I am pleased with now. At first I was very frustrated with this rifle until I started to try some of the tips given in the FAQ section. Now it is a descent shooter (~0.9 to 1.25" @ 100 yrds), but with more time, tinkering, and load testing I hope to make it even better. The biggest improvements so far were from a trigger job, polishing the bore with Flitz, shooting 60+ rounds before even trying to see how it would group, learning to keep oil off the latch shelf, and to Full Length Resize only. In my rifle, Neck Resizing usually results in a pop open.
MOGLEY, I feel your pain. I have been trying to develop a load for the Nosler 55gr BT. I started with IMR 4895 because I had it already, but abandoned it for a powder with a better fill rate. I have seen H-380 and H-414 recommended often, but neither are offered in my local store. I have been experimenting with H-4350, but it seems too slow for such a light bullet. I suppose Varget will be my next powder to experiment with. Good luck.