1) that a rifle is a much much better weapon than a pistol if you want to fire with any accuracy either on a range or in a firefight. I have fired a pistol and a selective fire rifle (mostly in semi automatic mode) with live ammunition in a 'move and fire scenario' (Rather then a more conventional stationary range firing position) and I can confirm that you will be lucky to hit much at all with a pistol.... what' the typical effective range of a pistol in a 'combat' scenario?
This link suggests somewhere between point blank and 5yards (4.57m) which I would personally say is quite realistic (yes I know that you can train to improve on this and I'm sure the SWAT guys who daily train are a lot better..... but a 50 year old schools officer isn't going to be doing much high pressure pistol training)
and 2) that a rifle has a much higher muzzle velocity then a pistol and fire a far larger projective with far more penetration then a 9mm pistol round and with a lot lot more damage caused to any target hit