Dead on spife, 30br is for short range score shooting. Some cartridges arent designed for long range comps, 6ppc for example. It's awesome for pointblank to 300m br, but it gets its shit pushed in at 600yds by 6br. The 6br is a very balanced case/caliber ratio. Yes it can be a 20br to 30br, but that affects its downrange uses and adds limits to it. I liken this conversion to 6.5 grendel, you can shove a 150smk in it. It's got fantastic bc, but that little case doesnt have the ass to push that heavy of a bullet.
Also, of all the popular br derivatives for lr/match, they all have one thing in common, they're 6mm.