I've been trying to find an accurate factory load for my bull barrel .243. I've been blasting through lots of factory ammo in the process. The best I've found so far is the Winchester 80 gr PSP. Sometimes it groups less than an inch, sometimes more. Although Winchester sells it as a varmint load, I've been told it works quite well on deer.
I've resigned myself to the fact that I will probably have to reload for this gun to find a load that consistently shoots 1" or less; however, I haven't tried all the tricks yet, nor all the factory loads.