Technically I had the 20 gauge barrels on it yesterday but I have a set of the 16 ga. This is one of the Parker repro's from the 80's. The 16 ga barrels were made after by Kreigoff by a gent in PA who contracted out for (IIRC) 500 sets. I was going to use them yesterday but I have more 20 ga than 16 ga shells.
The Repo 16 barrels were made by Krieghoff, at the request of Tom Skeuse. He owned Reagent Chemical and White Flyer Clay targets and was the man behind the Parker Reproductions. A flood at Reagent Chemical ruined many of the 16 gauge barrels, and relatively few ever made it into production. The barrels were fitted onto Parker Repro frames by Krieghoff at their facility in Ottsville, Pa. Although the article below says the barrels went to Krieghoff..Still, you rarely see a set for sale..
Addition: CSMC made some 16 Gauge barrels for the reproduction. They had some fitting issues, and were not of the same quality as the Krieghoff barrels..
I've posted this previously....Your Parker Reproduction and 16 Gauge Krieghoff barrel story....https://shootingsportsman.com/parkerrepro/