I guess we all have our favorites and reasons we prefer or try to avoid certain rifles use.
I've used a browning BAR in 338 on a couple hunts, and found it worked very well,
I used hornady 250 grain over a mid range load of WW760
Id sure stick with the 338 vs the 6.5mm, In my mind Id be thinking , I may only get one decent shot, and a 225-250 grain .338 in the vitals is more likely to produce the damage Id prefer than a 6.5mm thats 60-100 grains lighter
BTW if you clean the bore very carefully
cleaning the bore Of each firearm with a lot of solvent soaked patches,
(old cotton sheets cut into 1"x3" rectangles work ok on most rifles )
and a brass bore brush until you have no trace of jacket or lead fouling,
then , after the bores squeaky clean, soaking a couple patches , until they drip, with moly spray and working it back and forth in the bore surface, and repeatedly soaking those patches with moly, to coat the rifling with a good film of moly, then swabbing the bore clean with a solvent patch and dry patch, seems to very noticeably reduce future bore fouling
Moly exists as microscopic hexagonal crystal platelets Several molecules make up one of these platelets. A single molecule of Moly contains two sulfur atoms and one molybdenum atom. Moly platelets are attracted to metal surfaces. This attraction and the force of moving surfaces in contact, rubbing across one another provide the necessary thermochemical reaction necessary for Moly to form an overlapping protective coating like armor on the rifle bore surface, This protective armor coating has a number of properties that are very beneficial for your rifles bore surface
The Moly platelets that make up the protective layers on your bore wall surfaces slide across one another very easily. Instead of metal rubbing against metal, you have Moly platelets moving across one another protecting and lubricating the bore to projectile surface contact
This coating effectively fills in the microscopic pores that cover the surface of all micro bore imperfections making them smoother. By filling in the craters and pores Moly improves this seal
This overlapping coating of Moly also gives protection against loading (perpendicular) forces. The high pressures that occur between these moving surfaces that tend to squeeze normal lubricants out.