Normally a gyro-TWT is highly unstable. Instrumental for stability achievement was the use of a high gradient magnetic coil on the output. We have made experimental measurements showing that the TE01 mode absolute instability oscillation threshold is increased as much as a factor of five with modest output coil suppression field. Improving the electron beam power and quality is essential to increasing the power and performance of the gyrotwt. We have designed a new magnetron injection gun (MIG) with alpha= 1.5 and calculated axial velocity spread.