Construction and impact speed matter just as much as "light or heavy for caliber". If speeds are getting cranked up due to light-for-caliber, I'd prefer tougher construction. If speeds are lower, due to heavy-for-caliber, give me softer construction. Assuming medium game here. I've seen a 130gr .30cal mono bullet work at 3,350fps, but really no better than a 200gr .30cal cup/core at 2,650fps. Lots of ways to skin that cat.
Yes, my take on the subject is it is more a question of light or heavy for CARTRIDGE. 130's or 150's might be the ticket with a 308 but are ridiculous in a 300RUM. And while 200's or 220's work great in the RUM, they are getting a little slow and thus a rainbow trajectory with the 308. With lightening fast speeds meat damage is a greater concern, with slow speeds ballistics get more complicated. And as stated above, bullet construction is another factor. Choose your poison.
