Ok Here goes.
Hey there:
I assume by your post you can shoot. Good got that out of the way.
Here is my load. I have tested many, many, many, so no arguments here.
This works in my gun . Same twist.
80 grains of Pyrodex "P"> Remington Muzzleloader only 209 primer> 300 grain
SST/ML, 300 grain T/C shock Wave ( Blue tip or Yellow Tip Black sabot only)
Even the 250 and 300 Grain Red HOTs by Knight. These will all touch holes at 100 meters. My barrel must be swabed between shots. My sons rifle has a slightly larger bore and does not like cleaning between shots.
I can get under 1/2" groups ( center to center) with anywhere from 70 to 80 grains of that "P"..... That powder will not hurt your gun. BUT !!!! do not load Magnum loads with "P"... Much over 85 grains and accuracy goes away.
These loads clock around 1550 to 1600 in my Encore and produce extremely tight groups and kill critters very well. I hunted with the Red Hots this year as did my son. We took 8 deer total and recovered a few bullets . The expansion on the Red Hots is awesome. Most of the time 100% expansion and zero weight loss. Hard to beleive with a bullet with that large of a hollow point but they are deadly accurate. The SST/ML is the same bullet as the T/C shock waves and are made by Hornady for T/C. The Red Hots are Barnes MZs.( all copper bullet). I know you said you do not care about hunting, thats fine. The accuracy is what I am describing here. Others read this too so I tossed in the performance end. I have posted this before.
"P" works very well for target shooting because of it's pressure curve, it is more consistant then RS or the other equiv. I tested the clean burn powders and never found accuracy from my guns. Did not care for the smell either.
My testing was not some over the hood of my truck thing. I use a good bench with chrono, and chart every thing. Up to deer season here in Mich. This year I had tested over 700 rounds. Litterally burned out a breech plug.
All of this testing was done with a good 3x9 scope and I feel I could have done better with a higher power scope.
Hope this helps. There is a good reason for each component as listed.