I think that with Monometal bullets we can use lighter for caliber bullets at faster velocity and those bullet will deliver more Momentum at distances past 200 y than heavier ones.
I am using 150 gr Barnes TTSX for this very reason in my 3 30-06 ( When we go hunting together with my Sons we all have same rifles, same calibers 30-06, same scopes and same handloads.)
Hornady 150 gr SST we use for plinking, they would kill but I trust coper more.
IMO Very good Article explaining energy transfer, momentum ....
all would benefit from reading this.
http://www.gsgroup.co.za/articlemomentum.html