Mike,
The best way to shoot small groups is practice. Like the old saying goes, "How do you get to Carnegie hall, practice, practice, practice."

Some other things to consider, you need a good solid front rest, (A bi-pod or a mechanical rest, or even sand bags) and rear bag to shoot small groups. A simple set of wind flags will make a heck of a difference, all you need is a few pieces of surveyors tape out at different yardages. (set around 10, 40, and 75 yards) A good scope is a must, it don't have to be expensive, but it has to function, and having a light cross hair helps. Get some small dot targets (Wally world has them.)remember aim small shoot small. Last, try some other powders The ticket in the 1 in 9 223s looks to be N133 with a 52/53 gr match flat back bullet, I have seen a few guns shoot 5 shoot 100 yard groups down in the .2's. (Remember what works in others gun may not work in yours, and vise versa so it takes some experimentation) PLAY WITH SEATING DEPTH !!!