I have these 2 barrels. One is marked Strong Firarms Company New Haven Conn.
The other one has the same hook ups and looks the same. One is 32-40 and other is 40-50. 
What Gun would these be used for??? Thanks

The Strong Firearms Co. is best known for it's late-19th/early-20th century line of breech-loading "salute" cannons, used to start boat races, for example.  But they also made a tip-up, hammerless single shot that was available with rifle or shotgun barrels.  The barrels were interchangeable and multi-barrel sets are known.  They were quite strong and well made guns but also generally very plain.  Nonetheless, I once owned one  in .38-55 with a checkered pistol grip and forearm and a small Swiss buttplate.  If those "extras" were added post-purchase, they were very neatly done and consistent condition-wise with the rest of the gun.  In any case, Strongs were apparently not very popular as few are seen nowadays.  Grant's Still More Single Shot Rifles has a couple of paragraphs about them and also refers to them as "Dickermans", after the man who designed the basic gun.

Bill Lawrence