Here's a list of replacements from Track of the Wolf ML supplys
https://www.trackofthewolf.com/List/Item.aspx/807/1

The CVA looks like the 6-1 is the orig
#3 on the list is the 6-1 thread and for #11 caps.
They offer a 7-1 for a repair. You need to re-tap to the slightly larger size of course.
The first offering uses a musket size cap

They offer the taps as well, but those are standard metric sizes
https://www.trackofthewolf.com/List/Item.aspx/811/3