I don't dispute that but IMO It's a minimal gain for the work and money involved and the powder consumption in the RUM
Was just stating facts & not trying to minimalize the 7STW , when I look to working with high performance cartridges, powder consumption is never questioned, the minimal gain argument in the 7RUM vs 7mm STW is always presented with factory rifles/ammo and conventional bullets, when "doin a 7mm RUM right" you'd use 30" plus barrels twisted for 195-197 gr bullets and run with correct powders
if building both "right" from the ground up, cost will be same other than minor dollar difference in brass & powder expenses but there will be a considerable performance margin in favor of the 7mm RUM