I believe JB was referring to the 3700 fps remark from another poster.

As for powders making a difference the newish RL-17 is different. I know Bob Jensen and from what I have read German Salazar is the real deal. When they say that RL-17 is unique in delivering higher velocities in certain cartridges I believe them.

http://www.6mmbr.com/reloder17.html

I have used RL-17 and it really shines in the 6mm Rem and 284. It delivered velocities I have not been able to obtain with any other powder.