The artical about the heart valves and drama to the whole system was in Outdoor life a couple years ago. Some of the articals on Hang time were on the internet. I think from shooting times or guns and ammo. If I run on to them again I will post them. I have been interested in all thing guns since I was five or so. I like to know how things work. You can't learn to much and what I read, I try to prove in the field or apply in the field. I keep pretty close track of what has and has not worked over the years.