I still use FG Goex BP. I don't have a 50 caliber of any kind, though I used to want one. Untill i screwed my should up with the 45/70.

If you are using a relatively strong rifle, here is what I'd do............ My all time favorite duplex powder is 4759 because it's a uncoated powder and ignites well. I also only use 2 1/2 Rem primers with it. Although I have used 296 (45/70) and 4227. I only recommend the 10 - 15% with powders in this burn rate range. 

Start at 10% (in your case 9 gr) and work up to 15% (13.5 gr). 15% is the limit on ASSRA's BP rules. 

You should be able to shoot w/o wiping at 10% but, I've not dealt with Schuetzen powder or the 50/90 so, you'll have to try it out.  

Frank

Although Goex seems to burn a little cleaner I still have fouling issues here in Southern AZ. Over 20 years living in Europe spoiled me...

Guess I'll have to buy a different can of powder unless I can use 4064.

SS

Quote:

SS, how about some more details:
* Where is the fouling issue?  Near the chamber or near the muzzle?
* How many rounds for a shot string due you expect before you patch?  
* Have you considered blow tubing instead of patching? 
*  What is the usual Relative Humidity and Temperature when you have "terrible fouling"?  The issue could be due to the RH when it is 40% or less because as you know BP is hygroscopic and insufficient moisture is not entering the bore to moisten the foul
*  Details needed of the reloads that relate to the issue:  Primer - powder weight and granulation  - wad type -the bullet - alloy/weight and the lube you are using?  In addition are the cases annealed?  

Schuetzen powder made by Wano in Germany uses subcontracted Alder Buckthorn - the best wood for charcoal there is and in 2009 Wano reformulated their processing procedures to produce powder with an 8 - 10% velocity

I shoot a lot of Schuetzen in 45-70 and 45-90 reloads.  No I can't run 20-30 rounds in a shot string but have no accuracy degradation out to 500 meters with up to 5 rounds with good humidity - above 60%.  When I'm shooting 1000yds, I blow tube after every shot:  5 blows with high humidity and 10 blows with low humidity.

Why some many questions?  Because there are many factors other than powder that can cause 'terrible fouling'

I have no issues with my Schuetzen 45-70 & 45-90 reloads 

PS:  Based on multiple factors, you could have poor fouling with Swiss too.  I have when using FFFg 45-90 reloads in low humidity.  

Unique is definitely too fast for duplexing BP. I used to think 4759 was a good choice but changed my mind when I got flat primers and sticky cases with as little as 5 grs. My favorite for 30 yrs is IMR 3031.