Bahnzo

The other day my chain started skipping. Let me try to be brief here:

Replaced both chain and freewheel this spring...surely can't be worn in that amount of time.
Happens mostly in the middle chainring, but does as well in the big ring, just not nearly as much.
Middle Chainring was replaced within the last year or so, might be the issue, but I'm not confident there either as the teeth look ok, ie: they aren't "shark toothed".

So what then?? Could it be my derailleur? It's a friction shift, so it's not a problem with the indexed needing adjusted. And eyeing the derailleur, it's straight and in-line with the chain/freewheel cogs.

Could it be the derailleur teeth are worn? It's an 1985 Schwinn Passage, and it's the original part on there.

Thanks, I'm kinda stumped here right now.