Lancaster - etal, Thank you for all those pictures and comments, you have some good looking old guns to be sure.
I have a 71, 12gau. takedown which is quite nice and several 71-84s still in rifle form, none full military.
The 20gau. barrel is already 3" chamber. Getting any smithing done around here is difficult and time consuming. We have a shotgun only deer season, so I think I'll just leave it a slug barrel.
All take care --- John