> a rapid move
In that case Mach3 has the right calibration for the angle of rotation.
> decent speeds when jogging
In that case the system is mechanically able to rotate at a sufficient speed.
> feed moves at a rate of 7000 inches per min
Not so fast!
7000 UNITS per minute, but if you are using the A axis, that will be 7,000 degrees per minute. That is 7000/360 revs/minute, or about 20 revs per minute. That is 3 seconds per rev. Does that sound about right?
This is a problem when working with a rotary axis. Degrees/minute are very different from Inches/minute. In most cases the A axis will be the limiting factor in any operation. When I am programming g1 moves I do keep using different feed rates - depending on whether there is an A movement or not.
Keep experimenting - with all this in mind.
Cheers
Roger