unable to boolean subtract

 From:  bemfarmer
6671.5 
I copied the cylinder edge to make it a curve, selected the few points after it curves down, to the end, moved the furthest one from the end up
a little bit, with the rest of the selected ones following along, and then did the circle sweep over again, using the modified curve. A bit crude.

- Brian

EDITED: 4 May 2014 by BEMFARMER