Collision Problems !

OK, I need someone to explain me why does this happen :

I know its collision, because my players hands and pistol are out of capsule but check this :
Since that is not working !

I’ve done something aswell to check something about this. I’ve made a blueprint actor Box, and i made it to be in front of me wherever i go.
So i set Box collision to block all. And when i come close to wall it still overlaps and my weapon goes through wall.

So can anyone explain why does Capsule collision only working on Players Capsule and not when i add another capsule and i set same collision properties.
That second capsule is blocking other players but not blocking player from going through wall like the Inherited capsule does.
So why does that happen. I need answer if this is engines problem or mine.

I see that people are often asking this question but no one got any answer.

I can avoid this weapon going through wall when i duplicate the wall and make it bigger than original and setting it to be invisible so Players Inherited Capsule is being blocked by that second Wall and it will not let
me come any closer to wall to make my weapon overlap it. But what if someone is making really big game and you would need to waste a lot of time on doing only this. Thats why am i asking is there a way to avoid that
weapon overlap ?