Reports coming back that the 338 RCM aren't getting the velocities stated in the catalogues.

So the question is, are the velocities going to be the
same in the 416 ?

Comes down to my original point, Readily available brass - 416R - N', cheap brass - 416R = No. Plenty of 375H&H brass around.

What does the 416R give you that the other's don't,
except a new factory gun ?

Romance, short action - shouldn;t be a factor.

Short action - no action (except the Magnum Mauser) has ever slowed me up in fast shooting (and I have used a 375H&H Action a lot where 20 shots in 1 - 2 minutes was needed) and I don't think the short action would have made me any faster.