There is a jig made by Pacific Tool and Gauge that allows a bolt to be held in a lathe, so that the knob can be turned down. Saves a lot of grinder, file and hacksaw time, results are predictable. Just got one of these, and it makes the job much more straightforeward.
A 700 handle can be changed, but it is brazed on, so installing a new one is a pretty serious undertaking.