Need to place an order and I'm wondering what size of shotgun brush to clean an AK74 gas tube? One caveat, my gas tube is fixed because of an optic rail. I need the brush to be small enough to allow the bristles to flip and come back without the brush going all the way through the tube.

I use a 12ga nylon brush in the gas tube and inside the sight base. In fact, I have switched over and am using nylon for most everything now.