How long have you been shooting shotguns without the tacticool stuff? That's the question here, I think. What is a "tube barrel"? Not trying to be facetious here at all, I strongly advise you take the shotgun out in field configuration and put at least 1,000 rounds through it that way. Get to know a shotgun in it's original raw element. How it works, why it works, what it's limitations are. You can't even begin to grasp proper tactical modification and useage until you've mastered the basics. People who play the guitar usually start out playing other people's songs before they write their own, if you know what I mean. I bet I shot tens of thousands of shotgun shells, 12 and 20 gauge alike, through field/long/bird type guns before I even HELD a short barrel or tactical shotgun. Every weekend from 8 or 9 onward I'd be out with my dad draining box after box of bird shot. I still remember the first slug I shot. And of course the first 3" magnum. There's a reason I post in this section more than any others. I believe unlike pistol shooting and especially unlike Rifle shooting, shotgun is less cerebral than it is instinctive. The instincts it takes to operate, wield and maintain a shotgun for protection, sport or game isn't something you can just tap into. It takes trigger time and a lot of that barrel and loading port smoke and powder smell. A lot.
Just my .02