I'd like to suggest one, the National Museum of Civil War Medicine, in Frederick MD. It's not big, but has a lot of well-designed exhibits and good information- and useful information. I myself like looking at a rack of rifles and carbines, can be interested in variations on tape primers and tube sights...but the other end of the bullet trajectory is too often neglected. The advent of the rifled musket and minie bullet resulted in a lot more deaths but also more badly wounded soldiers, and the museum does a pretty good job of explaining what happened because of that, how the army surgeons tried to cope.

It is also convenient- about a half hour's drive from Antietam Battlefield. And ( merely personal opinion) there are some pretty good places nearby, with local beers, for lunch.

Hi there anyone interested in recommending things to OP! While you might have a title to share, this is still a thread on /r/AskHistorians, and we still want the replies here to be to an /r/AskHistorians standard - presumably, OP would have asked at /r/history or /r/askreddit if they wanted a non-specialist opinion. So give us some indication why the thing you're recommending is valuable, trustworthy, or applicable! Posts that provide no context for why you're recommending a particular podcast/book/novel/documentary/etc, and which aren't backed up by a historian-level knowledge on the accuracy and stance of the piece, will be removed.

I'm like week late to this one, but if it's arms you like, the best place I've seen is the Chickamauga Battlefield Fuller Gun Collection. It has hundreds of military and civilian arms from 1500s matchlocks to the World Wars. Lots of obscure, only-a-few-known-to-exist in the US guns as well.