Ok, here are my current patterns:

all based on Federal 00 buckshot and a mossberg 500 12ga.

I only had one 3" shell, with a full choke at 20 yards I had one hit in an 8" circle.

2-3/4" with Mod. choke had 3 hits in a 8" circle at 25 yards
2-3/4" with Full choke had 4 hits in a 8" circle at 25 yards
2-3/4" with Full choke had 3 hits in a 8" circle at 40 yards.

I think the 3" may have done better in a Mod choke?

With the full choke I never got quite 5 hits in the " vitals" but what I did get was a pretty consistant pattern from 25-40 yards. This seems pretty good I guess (i' m no expert at buckshot patterns) for deer.