Hazmat fee?

[Finn16]

If I purchase percussion caps and black powder online, can they be shipped together in the same box or will they need to be separated? I'm trying to figure out if I'll end up paying one Hazmat fee or two. Thanks.

 

[Heat]

Just ordered powder and primers last week. Should be only one fee. The primers were in one box, the powder in another, then both packed in another bigger box. All nice and tight.