So i bought my first semi auto shotgun last weekend.  I have been running a remmington 870 tactical.  I bought a 1301 comp 24".  Been working on reloads with it and haven't shot it yet.  So my question is when do you use the little button on the back of the lifter? I am guessing it will make more sense when I actually shoot it. But in the mean time it doesn't make much sense right now. Figure out the hard way you don't want to hit the bolt release when it is closed as it tries to ghost load 2 shells onto the lifter from the mag tube. I am sure this is quite entertaining for most of you, I understand that as I some what find it comical myself as I play with it.  But it is a real question.  Thanks guys.

Playing with it more last night, it appears the button is how you release a shell from the mag if you don't load one into the chamber.   Also appears no one is able to answer my question.

It ejects a shell out of the tube onto the lifter.

thank you!