I bought one (16 Gauge, blued action, english stock, choked IM and F) at auction, about NRA excellent in appearance, for $211.00. Discovered it had insufficient headspace. Had that corrected and have enjoyed it ever since.
Finding a used shotgun has insufficient headspace is an interesting experience. It suggests the 16 gauge shot shells for which it was intended (and presumably used!) had rims that were significantly thinner than SAAMI compliant 16 gauge shells.
Hope this helps some.
Warmly,
Kyrie
