My Handis do not include .223 but I have one in contender pistol. I get 5/8" groups with the white box. This was the best of the factory loads I tried by far. It took a while, but using less than maximum loads, 45 gr Sierra bullets, Varget powder, Norma brass, and a Lee collet die I got groups down to 3/8". A lot of work for a 1/4" improvement (but it is a hobby).
mike