I've just been reloading for a couple of months now, but in my experience all the manuals and data have been low.
In my .270 I've had to load 1gr (w/ CCI BR2 primers) over Berger's max for my velocities to be the same. On the other hand w/ Fed 215M primers I get the same velocity w/ .5 gr less powder.
So it might just be a variation in the power in the primer among other variables.
I just go up very slowly in ea. particular rifle until I start to see pressure signs, and use that info to set my max charge.
My rifle is a Rem 700 w/ a 24" barrel also.
Hope this helps.