Hi,I am in the process of writing a quick reference guide for people who use auction sites so that they will be able to get quick insightfull info on a lot of items from the civil war and indian wars,I have seen so many Items that are not correct and most people just don't know,and in truth have been taken.I have been repairing and restoring antique firearms for the last 25 years,and am an avid collector of cw and iw items.Example: the spencer carbine;The civil war carbine has a 22 inch long barrel,and 6 groove rifling.the 65 model has a 20 inch barrel also with 6 groove rifling.the 65 model made by burnside also has a 20 inch barrel, but only has a 3 groove rifling.there are other models,but this info should help you to make a quick ID.Joe