UPDATE:
The deposits in the barrel are LEAD! Could be carbon too, but it is LEAD!
Using .357 bullets and the same load of bullseye - still had lead at the end of the barrel.
Using the .356 bullets and Silhouette powder - had deposits.
Did try any other powder yet.
Jacketed bullets DO help clean the lead out of the barrel! Don't know how many rounds required, but after 18 rounds, the barrel was very clean - just a little left at the end.
So, I'm guessing what happened is, I didn't realize the leading was occurring when doing my tests, cause I did follow the tests with some practicing with my competition load using 124 JHP PD bullets.
So, Now to test in the Scorpion Carbine. Hopefully I'll have results that do NOT lead the barrel and can use up these bullets. So much for trying to go cheaper for competition loads. And I'm not even loading them very HOT. oh well.....