Why not an M16 variant? The government has wharehouses full of paid for M16's, that a local law enforcement agency can apply to receive, the rifle remains the property of the government, it's basically being lent, versus sitting in a wharehouse or heaven forbid chopped up and smelted, for which the government receives a bare pittance of the value.
M16 has nice ergonomics, can be fired by men/women of various statures, can be accessorised if need be, has a cartridge of sufficient lethality, is more accurate than most off the shelf hunting rifles, can stand up to a fair amount of abuse, unintentional or otherwise, something a tube fed magazine on a 30/30 (marlin or winchester) is not really capable of, one dent and it's down to a single shot, damage a mag on the M16, drop it an insert another.
2 rifles, an M16 variant and a precision rifle firing a longer range cartridge, out in rural area's you do have to deal with things other than the 2 legged problems and a rifle with more range an punch can come in handy and if you run into a barricade situation, where he has a rifle, then sitting within the 200 yard prime operational envelope of an iron sighted 30/30 is a bit silly, when you can sit out at 4 or maybe 600 if need be, with a scope mounted precision .308 and take advantage of your training.
Law enforcement personnel in the country, operate under completely different set's of conditions, than those in small medium and large cities. The cavalry may be a too far away to be of any use, so what you have with you, may be the only back up you have.
I carry spare rounds in the truck for my CCW, probably about 200 rounds and since I have went for an impromptu swim a time or two recovering vehicles,animals or other equipment, being able to switch out wet magazines and ammunition for dry ones, is nothing more than common sense, in my opinion.