Okay, now I remember where I got my info from.
Same place you did articap
From thread here on TFL IN 2009 titled:
triple 7 powder charge
November 10, 2009 06:36 AM
Where did you get that? Hodgdon`s web site says nothing of the kind. Their advice regarding reduction of the 777 load to get an equivalent Pyrodex load is not specific to loose powder; it applies to 777 in any form.
Don`t know what Hodgdon`s website says but on the container of 777 50grn. pellets I'm looking at it states '50grn. volume equivalent'. As a follow up to WHAT is meant by "volume equivalent"(equivalent to what) , ie equivalent to volume amount of 777 or volume equivalent amount of b/p or Pyrodex I called Mike at Hodgdon (#1-913-362-9455). His explanation:"The 777 pellets are designed to be the volume equivalent of Pyrodex or ffg b/p. Shooting two 777 50 grn. pellets is the same as two 50 grn. Pyrodex pellets or 100 grns of loose Pyrodex/ffg b/p. Shooting a 777 50grn and 30 grn. pellets would be the same as shooting 80 grns. of loose Pyrodex/ffg b/p. Loose 777 powder should be reduced by 15% when changing from Pyrodex/ffg bp to 777 and wanting the same charge".
This topic came up back in 2009 and I made the same call to Mike at Hodgdon. His exact quote above in bold black.