The gun appears to be all original and complete with it's brass firing pin, however the rear sight appears to be from a carbine (graduated to longer ranges) and the leaf is loose on the sight and not correct for the sight (see photos).

Based on the star at the end of the serial number it appears that this Model 1873 was made in either 1881 or 1882. It is believed that the star (which looks like a five-petal flower) was used by Springfield to indicate a gun which was made from a combination of parts and either held in reserve or issued to groups like the National Guard. This rifle is chambered in 45-70 caliber and has a serial number of #156185 with a star at the end of the number. This is a Springfield Trapdoor Model 1873 Rifle. Identifying and verifying the authenticity of an 1873 Springfield Trapdoor rifle or carbine is important in recognizing one of these weapons as a true collector's piece. Depending on the serial number, your Trapdoor could have been manufactured. Any information on this new puppy would be greatly appreciated.

The seller said it was a Springfield 1878 BUT it sure looks like a 1873. I just picked up a Springfield 1873 Trap-Door.

Springfield model 1873 serial numbers