How do I set up custom UCX collision without this error?

Hi All.

Video in here - YouTube

It’s bit laggy, dunno why…
Anyways, problem is that i made model at 3D max with UCX collision system.
Now in game engine, when i am trying to shoot somewhere near at “pilar”, this case it will collide some reason, and when i am stepping few steps forward projectiles fly as it supose, with no problems right forwards.

Hopely you got my point out of this text and video.
So any tips to say how to get it work better.

Ps. My main object is 2mm smaller than ucx collider, i don’t like that my gun is inside of wall…