Many cowboy shooters at the CAS City forum liked the Black MZ enough to buy cases of it. --->>>
https://www.cascity.com/forumhall/in...?topic=62087.0
And Curtrich's page titled "Black Powder and Substitutes for Dummies" which is about cartridge shooting stated:
"Every time I've done a Ransom Rest accuracy test, one of APP' powders has always won." --->>> https://www.curtrich.com/bpsubsdummies.html
I don't know if Black MZ was made to Alliant spec.'s like the Pinnacle powder was made slightly different for Goex, but APP 3F doesn't look as much like kitty litter and these powders can have a lot of different uses.
A person may like using a certain powder in one gun and a different powder in another.
One of the reasons for inconsistent velocities could be because it's a compression sensitive powder.
It produces higher velocity with heavier compression, and without enough compression then it will appear to be a weak powder.
It's just something to be aware of when describing its characteristics.