Here's something I posted a while back in another bear thread.

National Parks (US DOI) are far more strict when it comes to any sort of weapon, including pepper spray. There is an exemption for most parks in Alaska (Part 13) on weapons.

CFR Title 36

National Forests (USDA) seem to be much more lenient. Firearms are generally permitted, as is target shooting, hunting, fishing, etc. (under compliance with state laws). At least, in most forests. I'm sure there a few forests with tougher restrictions in place.