Sorry for seeing this so late.
I have heard Col. Grossman speak and found him to be very dynamic and full of good information. He really made me think with his views on video games/music/TV and movie violence and when you hear his reasoning, it is hard to dispute it. Of the people I have spoken to that don't agree with him, most are fans of the violent video games/movies/music and none can hold a candle to his background. That does not mean they can't object, but it also does not give their point of view much value. He speaks all over the world and I have not heard any other "experts" effectively refute his views.
Dave Grossman (author - Wikipedia, the free encyclopedia)
For me, I would go see him again in a heartbeat. I felt energized when I left the lecture, which was attended by cops, school officials/teachers, medical folks and other interested persons. As to whether he is anti-RKBA, I have not seen proof of that and he did not give that impression. He might be, but I do not know that for a fact.
Others might not agree, but I feel if you have a chance to see/hear him speak, take it.