I get excellent results from FC buck. It’s been a while, but like 12” at 25yds. Common buck usually does 25” ...
Never used FC in bird sizes.
If you’re getting 80% in a hand spread at 25yds, you better test that a few more times, then buy stock in that load, you found your goldilocks.
While I’m thinking about it, watch for the federal hi-bird shells. They confuse me. They don’t use a standard wad, and pattern like a normal wad with a mod, while using IC. Loaded fairly warm too.