Hydroscopic Silica Gel is OK; but it has to be regularly heated in an oven and dried out which is a real nuisance – Especially for someone living in college. Several of the large gun cleaning supply manufacturers offer rust preventatives. I use Birchwood Casey, ‘Sheath’ on the outside of any gun that I’m going to store for more than 3 months. Wipe the gun down with a little kerosene or a light gun oil before use.
In the alternative you might want to coat the outside of your firearms with regular automobile polish. Anything that contains Carnauba wax will work and work well. IOSSO makes a paste just for this purpose it’s called, ‘Gun Brite’. The advantage to using a wax polish is that it lasts a very long time and doesn’t need to be cleaned off the gun before using it, again.
To protect the bore I use the same highly effective, incredibly toxic stuff that Seal Team 6 uses: Sentry Solutions, ‘Smooth Kote’. I honestly believe that you could store the barrel in water after applying this stuff without having to worry about rust. It makes barrel cleaning ridiculously easy, too. Just make sure that you wear Nytrile gloves during application; (You should always wear gloves while cleaning guns, anyway.) and don’t get any on your skin – just inside the bore.
After many years of owning and caring for firearms I’d have to say that the best thing you can do to avoid rust on any firearm is to clean and oil it before putting it away. I usually do mine immediately after shooting - right at the range. (Saves a lot of counter space at home and, also, doesn’t stink up the house.)
Here’s the links:
http://www.iosso.com/metal.htm
http://www.sentrysolutions.com/SmoothKote.shtml
(a)
http://www.bostonindustrial.com/bostonindustrial/bit1.htm
(b)
http://www.bostonindustrial.com/bostonindustrial/062.asp
http://www.midwayusa.com/rewriteabrowse/1/678/655***658***
If you haven’t discovered, ‘Ballistol’, yet, most of my frequently used guns are coated inside and out with this completely non-carcinogenic, safe-for-your-skin mineral oil. Used in combination with IOSSO Bore Cleaner it will clean and protect any gun, no matter how fouled up, of everything except copper jacket residue. (Ballistol is listed at a very good price at the top of the Midway link I’ve cited.)
Good luck with school; it’s an exciting time in life; but remember to spend a few hours studying, too!