Weda , in a properly built gun with properly loaded ammo the 308 will shoot better than 99% of shooters can shoot it. Saying that one round is more accurate than another is kinda silly and if that were the case EVERYBODY would be shoot a 6mmPPC or 30BR as those to guns hold more records for tight groups.
Now I will say the potential for better accuracy is better witht he new Lapua case due to its desgine with the smaller flash hole and small rifle primer , its also a slightly more effecient case desgine so you can get about the same speeds with a little less powder.
I have heard alot of guys say the the 300 Win mag is a very "un accurate" round and can't be made to shoot well because it has such a short neck , and its funny that the 300 win mag has set alot of records at 1000yd matches.
If I building an unlimited bench rifle with one of these two rounds to shoot groups at set yardages out to 600yds I might choose the 6.5x47 over the 260 but past than I'm wanting a bit more power with the heavier pills and if shooting in matches where your actualy shooting the gun you won't be able to tell the differance ,you will have more accuracy variation with the bullets and primers than the differance in rounds will account for.
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