ORIGINAL: MLKeith

I did shoot over a chronograph. I had a lot of problem due to very heavy sun load and trying to shade the chronograph. It would record the shot but immediately cancel it if I was not quick I lost the reading. My accuracy suffered due to this. I shot 90gr. charges of Pinnacle and Black Mag'3 under a 300gr. Ranier cast bullet in a Harvester sabot using the .25ACP conversion with Winchester small rifle primers. I am wondering if using the hotter 209 primer might just clean up the fouling. I suspect that is what you were using. (Please confirm???). My comparison results were as follows:
In the .50 Omega"
Black Mag'3 1930fps.
Pinnacle 1350fps.

In the .54 Hawken (75gr. powder PRB Ballistol patch lube cci magnum cap)
Black Mag'3 1000fps.
Pinnacle 1233fps. (little spread 1233,1232,1235)

In the Omega (shot a few 300gr. Saber Tooth with 90gr. charges)
Black Mag'3 1700fps.
Pinnacle 1350fps. (big spread)

These were only three shot groups and volume measured only (not weighed charges)
As you can see this powder seems to be made for the sidelock .54 although I have to do a lot more before I can comment on accuracy. I just got the rifle so I don't know much about it and what it likes.