Hey GH,
Welcome............
Try some IMR 4198 in that TC. I went through several accepted powders for the .223, W748, BLC2, 4895, etc., etc.
Although they weren't terrible or nothing, I knew that the gun was capable of better.
I tried 4198 at 20.5grs and a 55gr Vmax, which was below maximum, and worked up from there to settle on 21.2grs.
I'm using military brass and Winchester SR primers. My accuracy went from over an inch, to a tight little cluster of 5 shots at 100yds.
If I do my part at the bench. I can keep them all in a 1/2" or so at the same range.
Hope this helps.....
Take care,
Bob