Re: 6.5x284 ?
I've got a Lapua case in hand with a 140g. Nosler Custom Comp bullet seated,,, mics .294+". .297" would be about right,,,,, .0015" clearance on each side. C.I.P. drawing shows 7.53mm which is .2968" (calculated).
"Shoots real good!": definition; it didn't blow-up in my face.