I purchased two pounds of this stuff a couple of years ago from a buddy at the range. At the time, I was just happy to be purchasing any black powder locally instead of having to order it online with the attendant hazmat fees.
After my initial elation at breaking 1,000 f.p.s. with FFFg, this "Cartridge Grade" is a real drag. My first mistake was probably dropping the powder charge from a true 40 grains by weight down to 37.5 grains. However the chronograph results revealed a tremendous velocity loss that I'm sure has more to do with the grade of powder than the 2.5 grain drop in powder. 37.5 grains of Goex Cartridge grade powder compressed under a lubed felt wad and a 255 grain LSWC "Keith-style" 452424 bullet (crimped in the groove) gave me about 750 F.P.S. out of my 7.5 inch Colt 3rd Gen. Single Action Army. This was originally intended to be my rifle load, hence the lubed wool felt wad to add additional lubrication. Out of my 24 inch Rossi Puma, it made only between 950 and 1,000 F.P.S.
A second variation omitted the lubed wad and seated the "Keith bullet" over the front driving band. This upped the velocity to about 800 F.P.S. with the revolver. The rifle stayed about the same. As a control, I fired my older load of 40 Grains Goex FFF under the 255 Grain 454190. It gave consistent velocities in excess of 1,000 f.p.s. out of the revolver and 1250 to 1300 f.p.s. in the rifle.
I expected "some" velocity loss with Cartridge Grade over FFF, but 200+ f.p.s. ?!
I just finished loading 50 rounds using the same Cartridge grade powder but with a full 40 grain load compressed enough to seat a 452424 over the front driving band. Probably a waste of my time experimenting anyway, since Goex quit making the cartridge grade some time ago. And perhaps it seems silly of me to fret so much about velocity when so many more content shooters concern themselves only with accuracy. But I was really pleased when I was able to achieve"original" velocities using the FFF load. Why else was I shooting a Single Actino Army .45 other than to experience a bit of history? So although I was mildly concerened when that FFFg ran out, and I had to fill the powder measure with the long ago purchased Cartridge Grade powder, I was unprepared for that great a loss in performance from one grade of powder to the other.