[FireHorse]

For a similar situation, see the 'Castaways in Time' series by Robert Adams, in which some modern folks on a hunting trip get transported to medieval Britain — along with their modern toys, including not only their guns but a couple of jeeps.

As you would expect, those modern toys don't last forever, but they give the characters an enormous initial advantage.

And then they exploit their modern scientific knowledge, which proves far more valuable in the long run.