If you want big, the .50 fat mac has it all, or how about the .585 Nyati? But as for the .308 being insufficient, ask all those dead enemies of ours when you meet them in hell. Snipers know the truth. As for not big bore .308s, what about the Cody Express, 250 grainers at 4100 fps, sounds big to me. Especially when your BK101 actioned, 26 pound rifle delivers just over 159 lb.s of free recoil. The .338 Lapua will knock your block off at a mile and ask for that your car be next, sounds big to me. As for making noise,
anything that burns 100 grains of powder or more is a sure crowd pleaser, .416 Rigby, .460 Weatherby, .50 BMG, so on.