The below links are from a quick google search of "firearms on BLM Forest Service land". I'm a registered pistol permit holder. I also have a modest collection of domestic firearms (No military-type, large capacity weapons). I used to hunt when I was younger, but now realize most of my missed shots were intentional. Regarding firearms on BLM or Forest Service land, I am of mixed feelings. I enjoy carrying a firearm, for safety and security, and because this is America, and I just can. However, I believe I am a respectful and RESPONSIBLE gun enthusiast, and conduct myself as such. Unfortunately, there are way too many of the other kind, good ol' boy, gun totin' cowboys, making life uncomfortable for everyone. To address Mark G's specific comments about the people with guns at DCHS, we had this discussion before about Jobe having a rifle pointed at him at Bowen ranch. The point I made at that time was that there are two issues. One is that guns are legal on BLM land, plain and simple. However, the second point is that having a gun pointed at you in a threating manner is definitely a violation of several laws, whether the presence of guns is legal or not. So, if people just showed up at DCHS with guns you would probably be wasting everyones' time reporting them. But, if you feel they were behaving in an unsafe or threating manner you would definitely be within your rights to report them, and I would encourage you to do so. The bottom line is, stay safe, and DO NOT PROVOKE A CONFRONTATION!!!
http://www.publicland.org/14_position_statements/PLF_2010_13_recreational_shooting.html
http://www.blm.gov/ca/st/en/fo/folsom/hunting.html
http://www.fws.gov/whhcc/doc/draftBLMshootingsportspolicy.pdf