Tubing the gallery with a twist

I don't know, I'll have to call ken and ask. I thought he said "barrel" lifters ? I thought it had something to do with the under ground cam? I pictured them being a little smaller in diameter at the ends like a barrel? ( it wasn't explained that way but that's the way I had it in my head) It was a couple years ago now so I may have heard him wrong or something. It could have had to do with the application and I was under the impression that they were a little more expensive. I pulled the heads and the Push rods out but I'll be damned if I've ever pulled the lifter out. and I think it's the only part that haven't had in my bare hands, those lifters...
good Lord I need to make clear that they're not roller lifters they're solid lifters. I'm sure that makes the whole difference. I'll be damned if I don't get into that motor next time and pull one out and look at it.