There are some cap vendors that offer flat rate shipping apparently without any hazmat fee.
One such outfit informed me in an online chat that they are not currently shipping any primers or caps, even though the web page didn't specify that.
But perhaps some of the other vendors are shipping, although they don't have any Remington #10's.
I found the vendors below by using an online search engine for percussion cap deals.
If someone can use another size and brand of caps, some will let a person purchase online.
Or they can call and inquire first.
1. Remington #11's in stock @$6.26 + #10.95 flat rate shipping. --->>>
https://gunstuff.tv/product/remington-ammunition-x22619-percussion-cap-11-percussion-caps-100-50/
Shipping can be delayed 1-2 weeks due to the Covid slow down.
2. CCI #11's in stock @ $48.85 + $14.99 flat rate shipping. --->>>
https://lockedloaded.com/product/cc...black-powder-solid-brass-10005#product_detail
They also have CCI #10's in stock.
3. CCI #11's in stock @ $53.99 + $9.95 flat rate shipping. --->>>
https://www.drgunsupply.com/search?q=percussion+caps
They also have CCI #10's in stock.