Your speed is a tad low..Have you chrons'ed any other loads to see how the speed campares.... you're right at 3100 for the RUM...Accuracy is more importaant than speed IMHO..H-4831 is alxo a good powder for the 300 Win and might give more velocity in your gun if you feel that you need it... My barrel on my 300 Win is 3" longer than yours... I am getting 3073 FPS out of mine with the H-1000 load... I got 3150 FPS with H4831,but liked the lower ES wiht the H-1000.....Is your rifle a factory rig or a custom???
range it,check the wind, dial in correction, aim and only one shot