Long story short, this was not successful. I'd worked up a successful load using the 2-3/4" Federal clear plastic hull available from Ballistic Products using 40 gr. Blue Dot / Fed. 12S3 wad / Fed. primer/ Lyman 525 slug w/ knurled edges and hot glue in cavity. Decided to reduce the charge wt. of BD and replace the resulting decrease in volume with WC 860 purchased from Jeff Bartlett. A check of powder densities showed 40 grains of BD occupied the same volume as 60 grains of the 860. I reduced the charge of BD in 5 grain increments from 35 to 15 grains; loading 4 rounds at each reduction in charge wt.
Velocities in relation to charge wts as follows:
35.0 BD / 7.5 860 - 1387 f/s avg.
30.0 BD / 15.0 860 - 1293 f/s avg.
25.0 BD / 22.5 860 - 1185 f/s avg.
20.0 BD / 30.0 860 - 1069 f/s avg.
15.0 BD / 37.5 860 - 863 f/s avg. (two rounds only)
A small amount of unburned powder was found in the barrel after firing. The muzzle was bumped on a clean board and the unburned granules were a flake type powder; which puzzled me, as I had expected it to be the WC 860 which had not been consumed. No ball powder granules were found among the unburned powder particles. The reduction in velocities made me think the 860 was not igniting or was only partially igniting. I'd like to hear opinions from those who might enlighten me as to why the increase in overall powder charge didn't result in increased pressure/ velocity. The 40 gr load of BD was chrono'ed the previous weekend at 1507 fps. Again; I'd like to mention the firearn used was a Savage 212 bolt action with rifled tube. Accuracy decreased as overall charge weight increased; about 5" group at 50 yds with the 35/ 7.5 gr charge and two of the last four in the 15/ 37.5 missing the target completely; these being hangfires which the chrono did not pick up.
Any thoughts?