I was able to install an anti-double feed detent on my Hammer. A few minutes with a drill and small file, quite easy. I'll post some pictures tomorrow if you want.
As for roll-outs, I use a barrel kit on my Hammer. It's spyder threaded (well, close enough, they could have cut the threads in a bit farther into the body), so I use my Freak kit on it. You'll have to remove the insert from the inside of the pump handle to fit larger diameter barrels. Just remove the screw from the front bottom of the pump handle and slide out the insert.