I love my 284, but think one of the ~45gr powder 6's or 6.5's is a better choice for real tacmatch use:
Less recoil
Prolific brass
Equal (or better) ballistics at "average" tacmatch yardages... Why use a rifle ideal for the 1000+ yard shots for a match whose average target is ~600 yards away?
While I run my 284 on a magfed (Alpha type 3s) short action, most people do 284s on a long action, which decreases magazine capacity - not good for tacmatches.
The 284 takes over for the 6s and 6.5s at about 1000 yards, but inside 1000, the 6.5s give just about nothing to the 284 (particularly with the 175-180gr bullets) and the 6s match it in wind and are about a whole mrad flatter.
WW hasn't made 284 brass in a couple years now, and they aren't even planning to make it again for at least a year. Do you want to be shucking Lapua brass out at a tacmatch? Do you want to be shucking out irreplaceable WW Super brass at tacmatches?
The decreased recoil of the 6s and 6.5s makes barricade/positional shooting easier than the 284.
I think an XC, Creed, Competition Match, x47L or Super LR in 6 or 6.5 is the way to go.
Being "Mr. 7mm", I hate to admit this, but for gaming the tacmatches, the 6 is the hot ticket.