@ 40 years old
The gun was made in 1915.
Where ti sth sreial number on the paidar barber chair
The highest for Colt 1851 navy original was only 215348 in 1873. Yours must be a reproduction model?
If you bought the gun from a gun store, the gun store will probably research it for you, but they may charge a fee. If you bought if from an individual and don't have any kind of bill of sale or other paperwork, you probably can't get it.
Crosman currently owns Benjamin & Sheridan air rifles. I'm attaching a link to Crosman's (Benjamin / Sheridan ) database of serial numbers. However there are no sreial records before 1983. But if you have the model number the records go back to 1882. See the link below
There is a problem with identifying the dates of Diana air rifles. Diana made air rifles in Germany before WWII, during the war the Germans made them switch to firearms for the German army. After the war the Allies broke up the Diana plant and sold off all the machinery. Some went to the Millard Brothers in Scotland and became "Milbro". Later Diana finally got he rights to the Diana name but had to make air guns & rifles for other air gun companies. Today Diana is back making their own air guns and rifles. You can try and contact Diana to see if they can help you. See the link below . Remember to switch the page to English. You will find the English tab at the upper right when the page opens