I recently helped build a 264 Win Mag with a 1:7" tight twist barrel (Shilen SS match) for the heavy slugs. I also helped develop the loads for long range Deer and Elk. what I have noticed is this. the newer 6.5's really do not work well for anything past 300 yards. they are constantly being put together with barrels for lighter slugs (1:9/1:10") and no one bothers to call out the MFR's on this. I went to gunsmithing college while the 6.5-06 was getting started as an alternative to the 30-06, 270 Win, 280 Rem/AI. I was severely unimpressed with the 6.5-06 until the the AI came out. I am still mildly impressed with it. I know it is just me. I like the 270 Win. It's a personal choice. the 264 Win Mag with a 1:8" or 1:7" barrel twist does a better job at long range than any other .264" cartridge in my book.. not too much recoil like the 6.5 Nosler, better weight carrying power than the 6.5-55 Belgium (the "swede" was developed and used by the Belgians long before being adopted by the swedes. Please stop using the wrong country of origin). I have already stated I am underwhelmed by the 6.5-06 so I will bypass my real feelings of this round. this 6.5-300 W/M is a new wildcat I had never heard about, but I am not too much into the wildcats so I am not surprised I know nothing about it. truth be known, I do not like any of the .264" diameter cartridges, I am just looking at the cartridges as a group and determining by my own values and stats what would be the best. the king of 6.5's in my own mind is the 264 Win/Mag. Agree with me, disagree with me.. I do not care. on each of the cartridges merits I have determined the Winchester to be the best. Later Tatters. I have to do battle with Braz-tech International.. common name.. Taurus of Miami Florida..