I've hunted with a 20ga for years. Ran across a Rem 870 28ga. Good news is the 870s use the same frame as the 20ga in the 28 and .410, so all my stuff from the 20ga fit the 28ga. I didn't want to alter the receiver of the 28ga in case I ever decide to wing shoot with it, so I went with a B-square to attach the red dot. The barrel is a fixed mod. At 30 yards with TSS, it's plain nasty. Marginal at 40 yards, so I decided not to send the barrel off to get cut and threaded for chokes.
Here's the 1st bird I killed with it:
Took all the wood furniture off, and put a set of Remington Sure Shot 20ga stocks on it. Forearm is a little big, but it works. Plan on trying to kill a slam with it before I move on to the .410. Running 1 3/8 TSS #9.5 handloads.