Trapdoor Springfield number look up

Hello all,
I was wondering if anyone can tell me when my trapdoor was made and possibly to whom or where it was issued ? The number is 317806

Thank you!
Kevin

Should be a cartouche stamp on stock for year 1887. Once in a while you get lucky in this case not. Serial numbers are listed in SRS for 317802, 317803, 317805, 317807 and 3217816.

Oh ok, thank you very much. Too bad the surrounding numbers are listed but not that one.

Thanks again