You're not talking about handloading "modern" .30-06, you're talking about loading an over-pressure .30-06 +P or whatever you want to call it.
Everyone knows that literally any cartridge can have it's performance improved by increasing the pressure beyond SAAMI spec. That's obvious. It's also pretty obvious it's not safe to do without either a) having the brass and gun manufacturers OK the higher pressure or b) doing your own engineering calculations that show the higher pressure is safe, with substantial margin. As far as I know, no one has ever done either of those things for qa .30-06 +P. I don't have a problem with hotrodding cartridges, and the .30-06 is a really good candidate because there are lots of easy-to-fix bad decisions designed into it (which was my original point). But let's not skip the safe engineering part, and let's not pretend the result is the same thing as the original cartridge.
