I have never had a close encounter with a live Gbear. I was in a camper when this was taken at the farm in AK.
http://i72.photobucket.com/albums/i199/DPhariss/AKbears1lr.jpg
they used to come by several times a week being "dump bears" from the Delt Jct dump. So it was a good idea to be aware when stepping outside at night or in the AM.
They like to look in widows and such too and will enter houses or cabins even when occupied.
But know some people who have gotten too close a few times and know a researcher who knows bears extremely well and has 2 books on Gbears and their behavior.
http://www.liveleak.com/view?i=71e_1191606630
Gives a pretty good idea of the time frame of a 20-30 yard bear charge. Sometimes its much less since the bear may approach within feet before the human or the bear is aware of the other.
If you watch the video the guide got his big Smith out when he saw the cubs. He KNEW trouble was on the way. He was knowledgeable and cool under pressure.
He turned the bear without killing it. This is OK but with a ML you only have one shot and it cannot be wasted.
Pepper spray is problematical from reports. Gotta have the bear coming up wind, gotta have it IN YOUR HAND, which is a problem in itself. Then you risk pepper spraying yourself, then there is a very real possibility IT WON'T WORK. Due to many factors. Note the guide in the video did not use pepper spray
I will not carry bear spray. I carry a gun. If the bear is going to cripple me for life or kill me I want at least one bullet hole in the bear so someone will know which one it was.
This keeps me from having to decide at some high stress moment "should I get out the pepper spray or should I shoot". I shoot when the situation requires self-defense. I have had a plan for this for decades because I frequent bear country, almost always alone and finding fresh tracks is not unexpected. Yeah the plan never works since its impossible to plan for everything. But the mind set is still there and this is important as well.
Lewis and Clark were amazed at how tough the bears they encountered on the great plains were. But note that none of the bears they shot with their 50 or 54 caliber RB rifles killed or mauled any of the party. They got chased at times, but apparently the 50-54 caliber ball was well enough placed to sufficiently hurt the bear so that it could not overtake and kill or injure the shooter. Bears are VERY fast and can reach full speed in a very short time since they are very powerful for their weight, outrunning one is simply impossible if the bear is not seriously injured. They can overtake and kill running horses with a paw strike if they can get fairly close, 50 yards or so.
There is no time to plan, there is no time to climb a tree it will occur in SECONDS in most cases. Videos of bears and accounts from people I know point out that the speed is simply jaw dropping.
You must have a plan.
One that works probably as well or better than pepper spray in SOME instances is to make yourself look as tall as possible. This from Doug Peacock who made close encounters with a Gbear his life's work and he is still doing it. A conversation with him is very enlightening since he has had to stand firm and face down bears in the course of his work.
BUT Peacock is EXTREMELY woods savvy. He knows not to get too close. He knows that an aroused bear or a bear that hates people is different than taking pictures and notes unseen from 200 yards away.
If you startle a bear, the bear or you approach too close, the bear is guarding a kill or cubs, the "problem" bear is still upset over someone darting/trapping it and hauling it to your location to be dumped on an unsuspecting public it can be very very bad.
So its best to carry a 4"-5" DA revolver of at least 44 mag with hard cast bullets for back up in case the bear gets you down. It may be of no use but it HAS saved people from mauling or further mauling and will continue to do so.
The only other alternative is to hope playing dead will work, but the bear may watch you for long periods to make SURE you are dead and if you move will return to finish the job. Hard to lay still for long periods after being mauled, or so I have read.
Dan