Post-apocalyptic TL 5/8

[sir_pudding]

I'm working on the writeup for my upcoming campaign The Blight Years. This game takes place a few centuries after a near human extinction and civilization has bounced back (albeit under constraints on areas suitable for settlement and severely restricted population density). The area in which the campaign takes place (in northern California and Oregon) is now able to maintain a TL5 industrial base but lacks the population to support TL6+. However, some knowledge and artifacts survive from before the apocalypse and they have some limited indirect trade with a TL6 culture.

What kinds of technology that's technically higher than TL5 should they still be able to produce (if any)?

What sorts of firearms are they likely to manufacture (and can I get away with just renaming some existing models)?