Yeah - good stuff.

However I ruined a barrel with Pyrodex RS back in the 70's. I would not use it today, if I were you.

According to Bill Knight who has done extensive tests on about all powders available, the perchlorates in Pyrodex, 17% of it's actual composition, is ruinous to barrels and brass alike.

By itself as in non-combusted, it is almost inert. Add heat and them moisture, it is poison to your barrel & much faster acting than standard chlorates used in corrosive primers of the past. Too - because of being 17% of your charge, it is many times worse than corrosive priming.

I would look into it, if I were you.

Graff's in the States will ship real BP directly to your door.

https://en.wikipedia.org/wiki/Perchlorate

"To continue a bit on that. (Bill Knight)
Few shooters today realize that the GOEX now on the market is a vast improvement over what had been produced in the old Moosic, PA plant.
The fertilizer grade potassium nitrate that Moosic was forced to use contained some residual unreacted potassium chloride. The process used by Vicksburg to produce the potassium nitrate was only 98% efficient. There was always some residual potassium chloride in the powder. Of course then in the residue. Making the residue extremely corrosive under certain conditions. And chloride salts are noted for both rust films and pit corrosion. When you read this think of the corrosive military primers used in the .30 caliber cartridges. Primers made corrosive by a fraction of a grain of a perchlorate. With the black powder residue well above that fraction of a grain in chloride content. As far as I could see none of the black powders being made today use a potassium nitrate that contains any unreacted potassium chloride. So while the powder residue might cause light rust films in the bore you will not see the nasty destructive pit corrosion seen in the past where they had to use a fertilizer grade potassium nitrate."

Now, hopefully you will do the math - Pyrodex's composition is 17% perchlorates. That means 17 grains of every 100 grain of Pyrodex, is perchlorate, not a fraction of a grain, or even a full grain, not 8 1/2 grains per 50gr. powder charge.