The trigger guard is very time consuming; it has a 100 ways to be off. The casting has to be bent back into alignment which is fairly easy with soft brass.
I took a piece of rect. alum. extrusion and put the two different heights on it.
Next time I will go with thicker wall alum. ext.
I have been trying to get to this stage since leaving the Chambers workshop and have been reading the Recreating the American Longrifle studying up for the brass patch box test.