You did not mention if this was CNC or manual, the principal many of the tube cut-off machines work, is a bar feeder arrangement feed the tube through the chuck to a programmable stop, when the chuck closes, the stop backs off to allow the tube to rotate and be cut.
This is assuming you have full length material to be cut into short lengths.
I just completed a retro-fit of an old Modern Tube cut-off that uses this method.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.