If you like to keep your long guns protected, then this may be of interest to you....
http://www.cabelas.com/product/Shoo...-racks/_/N-1100216&WTz_l=Unknown;cat104194980
I use gun boots off of ATV's and horses.
Pro's:
It will keep the rain, snow, dust, and mud away from it as long as the "lid" is secured properly. I once rolled an ATV down a rather steep incline once, while my M14S was inside the boot. Unlike the ATV, the rifle was fine.
This also opens up the door for a wide range of long guns and in several action types.
Con's :
It adds some bulk overall, and takes a few seconds to open the top and pull out the rifle. I generally leave mine secured as I have a tendency to push quads at speed whilst out riding them. ( The wife calls it the "Evil Canieval syndrome"...lol)
Rifles that sport large capacity magazines and pistol grips are not well suited for this type of transport on an ATV.
M1A/ATV specific things that I incorporate....
1. An M1A/M14S with a 20rd magazine inserted into magwell will not fit inside the boot. I use a flush fit 5rd mag in this regard.
2. Depending on optics/mount/rings, the M1A may not fit inside the boot either. I use an ARMS #18 mount on my M14S.... which sports a very low profile, and also use low rings to get the optic as close to the original "comb line" as I can. This not only allows it to fit inside the boot, but also provides for better cheekweld whilst shooting said rifle.
I use a Bassett mount on my M1A-A1, and simply remove the mount/optic/ring combo from the rifle, then re-install it when I got to where evers I am headed.... and without loss of zero.
My .02..........
I would not worry about a super compact SBR type of rig if your working off an ATV. A full stocked rifle allows for a better long range shooting platform in most cases, as compared to folder stock designs.
Besides, I could get to a rifle inside a closed gun boot faster than trying to get out a rifle shoved in a rucksack strapped to me back while riding a quad anyways...
Either way...... the rifle would be in my hands when I was parked some wheres... regardless
Note: I do not live in bear country, but have been on a few overnight camping adventures in said country before, and off of ATV/s as well as horseback. Critters to include bears dont seem to like the noise and smell produced by your typical ATV.
If you wanna see critters on your adventures, then horses might be the better bet.
I'm in the "matters little" camp concerning 308 vs 30-06. I also think that you should pick the rifle type that you are comfortable with maintaining, and that you shoot well with, especially if longer distances are involved. An M1 Garand alongside an M1A feel similar, but do have differences, like most others do.
Note: You seemed to be interested in semiautos, but there are a few lever actions such as the Marlin guide gun that are well suited to use from ATV,s and horses.
Note: An ATV makes for a decent shooting platform, although it might be a no-go to use it in said fashion for hunting. (Check your own laws regarding this)
Note: You have a much greater chance of getting into an ATV accident while out on the trail...vs bear attacks IMO.....and especially while your moving/while ATV is running. I would keep a decent aid kit on your person, along with a decent revolver in your holster personally. If possible, travel with a buddy whom has his own ATV. If he suffers from "Evil Carnival syndrome", have him ride out in front of you, as you do not want him running into you from behind at top speed...... ( Ask me how I know this, and where the wife tells me to be at while we r out riding....)
Also....... strap your ruck down to a rack, and wear a camel back. Best way I have found to stat hydrated while keeping both hands in control of your ATV all at the same time.
Good luck with your decision.
11B