Ditch the Pyrodex. Use a case full of black. If you want a reduced load you can fill the case with the amount of black you want to try and then fill the rest of the case with amaranth seed then the wad and then the bullet. 43 wads are available from Walter's wads.

Pyrodex will work fine in place of BP.often blackpowder isn't easily available in some areas.if available I would choose black powder though.
Don't be turned off by guys who hate the Subs, Have fun with what you can get
Im sure the "purists " all ride their horses to the range  cast over a fire and shoot only hand made rifles and tools produced on no modern machinery.I can't believe they shoot "replica substitute" rifles with "real"black powder .(I just had to poke fun at the blackpowder snobs )
I shoot mainly black and order 50# at a time and it's much cheaper than the substitutes.but I've had great luck with Triple-7,BH209,Black MZ and Pyrodex.

oneatatime's load data is great advice

I just  bought a Vetterli .41 Swiss here I'm shooting smokeless in.I've thought about using black but the load of 8g of Unique works so well and no cleaning required.
It's been tempting though.

Now I need to start by saying that I only have shot one container of Pyrodex and that was probably 30 years ago.  I was shooting 50 caliber muzzleloading rifles and then purchased a 12 ga muzzleloading shotgun for hunting.  Well black powder fowling had to be cleaned after several shots in my rifles so I bought a can of miracle Pyrodex.  Off to the mountains I went with my shotgun in the scabbard and sitting astride my favorite horse.  After about an hour ride I rounded a corner in the canyon and there were quail everywhere.  I bailed off and tied my horse up and put caps on the nipples.  I eased up and got two shots off as they rose and when I went to reload the fouling was bad enough that my wooden ramrod broke!  I was now out of commission.  My next trip I had changed to a fiberglass ramrod and away I went horseback again.  My experience that day was that there was a definite lag between the time the cap went off and the explosion of the charge that I never noticed shooting a rifle but trying to swing and follow through on wingshots it was obvious.  I switched back to ffg  and the lag went away.  I never tried musket caps to see if that made a difference as black worked better for me.  I now shoot Swiss 1.5fg in my 40 caliber bpcr guns when I shoot black but must confess I like shooting smokeless better.  The rifle is harder to clean with smokeless but the brass is so much easier than shooting with black that I get lazy and leave the black for a few of my rifles.  Tom

Redrighthand wrote on Feb 23^rd, 2022 at 11:38am:

Whoever didn't clean the rifle properly ruined the bore. Don't blame the propellant. And yes you can get black powder delivered to your door but if you're not ordering 25 to 50 pounds at a time like a lot of us do it's not  cost effective. If you order a couple pounds by the time you pay the hazmatand shoipping   it's just too expensive.its  convenient for many just to buy a pound of a substitute locally. As long as it gets somebody out shooting that's a good thing in my opinion.
Out here in Eastern Washington there are no places that have black powder and stock for people just to go buy a couple of pounds. It's kind of sad that nobody wants to take the liability with the storage.

Cbashooter wrote on Feb 23^rd, 2022 at 1:10pm:

Damascus barreled shot guns. The stuff started eating any imperfections in the bore. These guns never saw anything except real BP while I owned them and there were no problems. Until I used Pyrodex. Then that stuff started eating and I could never get it to stop.  I have used it in Italian repop revolvers and lever guns with no problems, no rust problems at all, so I guess it wasn't the guy cleaning the bore.
Real BP is so easy to get I don't see any reason to use anything else. I buy 10 to 15lbs at a time, usually at $20 a LB. plus the $35 hazmat fee for the box.

Pyrodex is much more corrosive than black powder. 
Lee Gibbs Pres.ASSRA