It looks like the show takes place 15 years later. I suspect those with guns are carrying muskets because it is easier to manufacture black powder and balls than it is smokeless powder and primers being that modern cartridge components have long since been used up.

I was a little turned off by the sword fighting too...

PS - I agree with the notion that the people would have started manufacturing again after 15 years with no electricity. Did we totally forget about steam engines and belt driven factories?