Touring with firearms = never

Touring with bear-spray in bear-country = yes

The likelihood of an encounter with a bear that would require either is minimal. Shooting a gun is a bad idea in a National Park and basically not allowed. If you shot a bear without being mauled first you'd probably end up being ridiculed by the entire world (like the guy who shot the lion). Using bear spray would be fine. Anyhow if you're gonna worry about anything you should worry about the real danger when bicycle touring CARS & TRUCKS!

On my trip to Alaska I used a bear canister (blue thing on top of rear rack in photo) and carried bear spray. I saw lots of bears but never touched the bear spray. The bears & I kept a good distance away from each other. RV's flew by me within inches