Hi I just recieved my first shotgun, specifically the Derya Mk 10 and I have a couple questions. The range I go to only allows the use of slugs and I'm wondering if I should be using rifled or non-rifled slugs? Also, am I suppose to use a choke? the gun came with a choke I believe and I heard I'm not suppose to shoot slugs without one (i cant tell what kind of choke it came with and is it hard to install a choke?). Lastly, does anyone have any idea what the tube underneath the barrel is for? Thanks!
here is a picture of the shotgun in question: https://imgur.com/a/iRW4l