they have everything Pietta and Uberti, or use Dixie Gun Works www.dixiegunworks.com
I ordered some spareparts from vti, especially the hand-assembly (exactly what your problem is) because it is known to give problems (when the revolver gets sooted and the cylinder is very hard to rotate).
Alessandro Pietta is one of 2 sons of Guiseppe (?) Pietta that run the company. In the last few years, it looks like they catched up to the quality of Ubertis, known as the best Italian revolver replicas.
For rifles, I think it's still Pietro Pedersoli.
THAT STUFF IS ADDICTIVE!