Coupler quite large
For my rifles, a model 12, Ruger Varmint and others I use a Chamber guide. The eye piece attachment is pretty large and as you use the bore scope and look at the rifling, the eye piece attachment is dragging on the stock comb and starts to bend the bore scope tube. It looks like the camera video system has a smaller coupler. The right angle is great if you don't want to take the stock off every time you inspect and clean your barrel. Do so will ruin your bedding and you'll have to go through torquing your stock all over again.
