What is a Cylinder choke? will it damage the new M4 (11707) barrels if I dont use it? I definitely want to shoot slugs through it. Why is a choke necessary? I thought that these were slug guns out of the box. Thanks for your reply, I'm a nooby when it comes to 12 gauge, like my other post says, this is my first shotgun and I have been waiting about 3 or 4 years for the M4.