What is the value of a Columbia 410 single shot shotgun?
Is there any other writing on the gun? Columbia was a trade name manufactured by the W.H.Davenport Co of Norwich, Ct, but I am not sure if they ever made a .410. There is little collector interest in single-shots and 2 1/2" shells are not available, so it will have little value. Since it was your grandfather's it should be priceless to you, but it would probably sell for $50-$75 today.