Even very ordinary mail doesn't have holes large enough for most bullets to pass cleanly through. They will have to break some links, just like a blade would.
Here's some mail with a ruler for scale
https://i.ebayimg.com/images/g/5vkAA...WEu/s-l400.jpg
So yes, for a magical material that's more than twice as strong as TL7 steel, why not DR 18?