I-too would dispense with using a smokeless powder to 'kick' off the rest of the charge. If you want to use something for that purpose, use 10% to 13% 3F black powder, and reduce the smokeless charge 15%. Please don't use smokeless for an 'igniter' charge, especially with an already fairly fast powder, like 4198. A pressure spike could destroy your rifle.
-------------------- Daryl
"a gun without hammers is like a Spaniel without ears" King George V