As Sitka noted, NAP moved their production offshore. They are quite inferior to those that were once produced in the US. I tried these offshore ones - first shot and the damn thing opened prematurely. Sent them back with a Never Again note to NAP.
I have around 15 or so on hand, and a few of the replacement kits that were all made in the US. When those run out, I too will be looking.
Never shot one. Best bet would be to inquire on the Excalibur Forum:
https://www.excaliburcrossbow.com/phpBB3/
KBC: Although one of the Ladz used to teach, neither he nor any of the others do so these days.
Sitka: Wise words as usual my friend. Appreciated. Have a safe & successful season up there!
Cheers,
Nog