I use an 20 ga 870 youth with the 21" barrel and load TSS. I drilled and tapped the receiver and mounted a Burris Fastfire 2. I did the same thing for my son. His 870 is the Compact Jr with an 18 3/4 barrel. He shoots the reduced recoil Federal HW #7's. He killed his first bird at about 35 yards with the combo last year. The 20 with the right ammo still amazes me.
A few pics...
How far was that pattern target? What restriction / make on the choke tube?
Indian Creek .555 -- TSS #9's. For some reason, I'm thinking 30 yards on that one? IIRC, that target was the first I shot after zeroing the FF2.
I enjoy handguns and I really like shotguns,...but I love rifles!