My thought is that the factory guns from weatherby (not including the 6.5-300 and 6.5rpm) don't have fast enough twist in the barrels to stabilize the heavy for caliber/high BC bullets that long range hunters/shooters use.

I guess I don't eat the lungs.

Swaro if it going to be used for hunting, for middle of the day range work anything will be fine.

 I just measured a factory 100g tsx coal at 3.123”

+3

168g BergerVLD and H4831........or use all of the available horsepower the 300 Roy gives you and step up to the 215g

Make sure you clean the barrel and when you think your done clean it again.  The Barnes bullets WILL copper foul you’re barrel like crazy, especially after you have shot a different bullet previously.  One of the reasons I will not use them.  Unless your hunting elk any non varrmint bullet will kill thin skinned game.  Pick the one that gives you the best accuracy.  On your guns accuracy,  a shot out barrel doesn’t happen over night.  It gets progressively worse, so I doubt that’s your problem.  Clean the barrel with some good copper solvent, it’s cheap and easy to do,..... and I bet it fixes your problem.  If it doesn’t, take your Vortex back and get another one.  I personally won’t buy anymore Vortex products  no matter how cheap they are or how good their warranty is.

I’ve had great luck with H1000 and 210/215g BERGER’s.