I'm using ADI2225 with 154gr sst, the same magnum federal primers and almost the same charge in the same chambering.
I have never looked down the tube between shots and just clean up after a blast so i can't say weather mine burns clean.
If you're not having any issues with accuracy and they are moving along at the desired speed I wouldn't worry about it.
"Black shit" as you say, is easy to clean and it doesn't harm anything,
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