Go to Google, select IMAGES from the toolbar, and for search term enter Iver Johnson double hammer shotgun.
It should be marked on the barrel or recieiver.
There is no "break in" shotgun. A "break open" shotgun is a single barrel, double barrel, or combination rifle/shotgun which breaks open in the sense that a lever will unlock the action, allowing the barrel to pivot at a hinge at the front of the receiver, pivoting the rear of the barrel up to expose the chamber. A shells may be loaded into the chamber and the barrel pivoted back to close the action. The act to "break in" a shotgun means to fire it a few times to loosen it up.
In reproduction catalogs from Sears @ turn of the century
Go to google and enter "20 gauge double barrel shotgun" then click the (images) button at the top of your screen. Then hit (search images).
yes they made a martini action single barrel shotgun 12gauge it is cheap around £100 but it has a huge amount of recoil you can buy them on guntrader.com
A shotgun barrel with a cylinder bore choke.
how old is my Iver Johnson single barrel shotgun champion model 3578 C with a 12 gauge choke bore barrel and lug forged in one and approximate value .
yes a rifled shotgun barrel or smooth shotgun barrel
In order to answer your question correctly,I would need the maker of the shotgun,shotgun model,and type of shotgun we are talking about(pump action,single shot,semi-auto etc.) I would also need to know what type of barrel you have(plain barrel,solid matte rib,or vent rib barrel).also include the overall condition of your shotgun and amount of blueing remaining on the receiver and barrel.
Check the receiver and barrel.