So I just picked up a Remington 870 Express Synthetic. The Remington site says it has a fixed choke. Being new to all this i'm trying to understand all this. I understand chokes as different chokes allow the bird or buck shot to stay in a tighter pattern or group or spread out more depending on the choke. My question is I want to shoot bird/buckshot and slugs at the range. Somebody I know mentioned to be careful with slugs cause if they don't fit you can mess up your gun. I currently have these slugs. Upon checking my barrel I see this below on the side. Would this mean the fixed barrel choke is a cylinder sized choke? And if so, can slugs be fired safely from them? From what I have found and read a cylinder choke has no restriction. I'd rather be safe than sorry which is why i'm asking. Gun in question: Wanna kill these ads? We can help!