Firstly, you do NOT want to be firing a rifle round upwards. Remember that law that says "Anything that goes up must come down.". Well, a rifle slug will come down, and with a high enough terminal velocity to be lethal. So, that's not a good idea. For that matter, firing a rifle into the air is illegal in quite a few places, due to the propensity to cause fatalities (Ok, so the military gets to do it for ack-ack rounds, but that's a rather specialized case.).
A shotgun, with suitably small shot (e.g., #8 bird shot, or #12, or...) will be effective up to about 50 yards, and won't constitute a lethal situation when it comes back down, mainly due to it's small mass to surface area ratio, and rather non-aerodynamic shape. Yeah, I've been peppered with falling bird shot, and it doesn't even hurt.
As for RF jamming the signals, that would be a bit of a problem, for a couple of reasons. Firstly, it's against US federal law to interfere with any kind of radio communications. Secondly, you really don't know what frequency the thing is operating on (27 MHz, 72 MHz, 50 MHz, 2.4 GHz, etc.). And, you're not really sure if it's using some kind of encrypted/encoded communications. Sure, you may blanket the entire spectrum with noise, and take out most of the emergency service radios in the process, but you may not do anything to the drone, which may simply remain in position with no radio signal to guide it.
If the thing is outside of shotgun range, well, one would presume that it's probably far enough away to not be a hindrance to any ground based emergency responders. And, if an air tanker happens to drop a load of water/fire-retardant on it, well, that won't be their problem, if this law passes.
As for someone shooting one down, one would presume that they'll ensure the likely crash area to be devoid of people/equipment before the shoot-down.