I have two sizes of bear cannisters:The classic NPS rental "Garcia", and a newer, smaller, "Bare Boxer" that is excellent for overnighters. When I use the larger can, I lay it sideways on my sleeping bag inside the bottom of the pack. The smaller can is upright on the bag, with the space next to it stuffed with tent, rainfly or other softgoods. I try to avoid strapping cumbersome items to the outside of my pack, due to the fact that I seem to X-country frequently. Like previously mentioned,I only store food that will be used the next day; the current day's food is kept in a more convenient pouch.
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