Old thread, but...
General Dynamics, St. Marks manufactures:
ALL Winchester-branded powders of all types,
All Hodgdon-branded sphericals,
All Alliant-branded PowerPro series powders,
Some Accurate-branded sphericals (2700 = Win760/H414, for example. Look for "Made in USA" on Accurate-branded spherical powders and you'll know it's a St. Marks powder)
Hodgy's Hybrid 100V as well, IIRC.