Hi guys, I am new to the site, and wanted to ask opinions on whether there is much difference between 338 RUM or 338-378 in hitting what your aiming at past 1000 yards. Friends I shoot my 300 and 257 MKV WBY's have the bigger rifles and I want to play far away too. I like the 338 RUM in Sendero, but would rather have a 338-378. Being that the 700 is preferred over the Mark V I am leaning toward a 338 WBY built in a custom 700 rather than a Accumark, which I would have close to the same money in after accurizing. Other than component cost, is there a major difference between the two in the real world? Or should I keep looking for a Sendero in 338 RUM?