I used the new brush today and I must say every auto loader owner should have one. I couldn't believe how much carbon came out of the cylinder. I also noticed that the piston moves easier in the cylinder.
It's a must-have for auto loading shotgun owners. If you use one remember to turn the brush counter clockwise so it moves the carbon, rust and fowling out of the ring.
The brush is tapered and it fits a wide variety of gas rings.