If this story is as reported, it is the first case I have read where a pump action rifle is used for the robbery. Pump action shotguns are much more common, so it might be a case of mistaken identification.
That was my thought, too, marktwain. If the "pump action rifle" had been in the hands of the law-abiding citizen, it probably would have been referred to as a "large caliber pump action sniper assault rifle equipped with a high capacity clip loaded with cop killer bullets," et cetera.
Other than nostalgia, not many advantages for a pump action .22 (there are some).