150m is perfect distance for assassination.

Target shooting ranges for full bore rifles are always > 100m. In competitive shooting competitions range is 300m free rifle/standard rifle from three positions (kneeling, prone, standing). In military sharp shooting competitions ranges are 500-1000 meters.

Military qualification ranges for service rifles typically test shooting from 150 and 300 meters.

Military sharp shooting ranges and competitions have distances >500 meters.

Not really, especially electronically controlled and aimed/targeted. Maybe they even used 50 caliber, just to be super sure.