Ideal bullet weight for a .308......ask a Palma shooter, 155. Ask a Marine, 175. Ask some other guy, 190. Which one is the best? They all are great choices. Neither one is going to hurt your ability to shoot long range, the important thing is to stop talking about all these crazy ideas and go out and shoot a bunch with a .308. You are talking about the .408, then the .338 Lapua, then back to .408, then a .30-378, then .308, .30-06 now .308 again. Get a .308, a bunch of Varget, any of the above mentioned bullets and spend as much time shooting that rifle as you do talking about it and you will do wonders for your longrange know how. After you have worn out your .308, then you will know what you want in a new rifle in addition to your freshly barreled .308 just because they are reasonably cheap to shoot, and not as tempermental as some of the exotics. Its pretty hard to not take a .308, 43.5 gr of Varget in a Federal case with a 175 gr match bullet jumped .010" and not have a gun that shoots .5 MOA at 2700 fps. It will stay supersonic to 1000 no problem. You will learn the effects of wind, mirage and changing light conditions. Keep a good log book of environmental conditions with each long ange shot and start a spreadsheet up that tabulates all the data. Master the .308 and you will be a serious threat at longrange to any steel plate, paper target or crow. JUST GO SHOOTING!!!!!!