Just got my first gun, a Remington 870. I have a field barrel on it. I took it off to transport the gun and just put it back on, and went out shooting. While bringing it into my house I noticed theres about a 1/16 of an inch gap between the barrel and frame of the chamber. The barrel freely goes back and forth in that small space, until it hits the chamber or magazine cap. Is that normal, or should I have it checked?