Some time before final release, there was a "fix" to players getting stuck on doors. The problem was where the player's weapon would get stuck on the door and cause weird instances of jittering. This worked for that problem, but it makes a huge hole in the realism factor. Currently both players and AI are able to stick their weapons through walls, walk sideways through doors with large weapons like anti-material rifles, and turn tank turrets around in alleyways. You can be shot from the inside of a concrete bunker purely on the fact that a disembodied arm with a machine gun decided to pop out of the wall. You can have people walk around in CQB environments with marksman rifles killing everyone. This is a major problem. You might not think so, but it really ruins gameplay & looks terrible. Now, if you did decide to fix this problem, the problem of getting stuck in doors might come back. My suggestion to fix this (For small arms) is to shorten the collision model of the weapon so that about 3/4 of the length of the weapon has collision. Then people would actually have to use proper room-clearing tactics and turn after breaching instead of "ghosting" through the door frame. Now for the armor barrels, those should collide with anything touching the barrel. It's really stupid when you trap a tank in an enclosed space and it just moves the barrel through a wall to shoot you. They used these tactics in World War 2!!! I'm pretty sure in 2035 they won't have magic rifles and tank barrels.