Thinking about buying a Tactacam camera at attach it to the barrel of my rifle. Will mounting it there have a negative effect of the impact point of the bullet?
Yes. Anything hanging off of or touching the barrel will change the harmonics. Tactacam does make a kit that allows you to attach it to the side of the ocular lens of your scope and see what you see. It is a bit more expensive but won't effect your POI and will probably produce better video, especially if you are shooting any kind of distance.