Thanks for the follow up - After looking deeper into this at http://illegal.gold/ and kitco's pages,
could only find evidence related to gold, not silver...
What I did find on silver said the purity may be possibly .993 - .998 but very rare.
Kitco still has a disclaimer on their silver page.
https://online.kitco.com/sell/1003B/Buy-Back-10-oz-Silver-Bar-999-1003B
Thanks, I will say it's a rumor that some Buffalo Rounds are showing .925 not .999 off their Sigma's