help me out here guys in not sure exactly what i have, i know its a conn and from what i can tell from the serial number its like 1946ish. im not sure if this is an 8d or what. it has USMC stamped on the bell, and i was told it was a ww2 horn used in the band... but ww2 ended in 1945 so the dates may be a little off. any way, i am trying to put a value on this horn because i really dont know what it is worth. i used it in middle school and it has been in my garage since then. its not the prettiest horn but it plays well and is actualy pretty straight no major dents or anything. the serial number is 356068, any light you all can shed would be a huge help. thanks
http://i299.photobucket.com/albums/mm287/jwmini/363b9579.jpg?t=1314111267
http://i299.photobucket.com/albums/mm287/jwmini/653e179d.jpg?t=1314111271
http://i299.photobucket.com/albums/mm287/jwmini/331f6f24.jpg?t=1314111247
http://i299.photobucket.com/albums/mm287/jwmini/0c32cb90.jpg?t=1314111237

Nice to see that horn. The serial number and location lead me to believe the horn was made prior to WWII. It was probably made in 1940-1941. The US entered WWII at the end of 1941 and the Conn factory retooled to manufacture needed supplies for the military (brass amo casings etc).

The layout is the same as Conn 6D.
Is it brass or severly tarnished silver?

Value?:
I have seen 6D prices all over the place. Generally they sell for $300-$600. However, a professional instrument, from the 30's well taken care of with some modifications I've seen for $3800. With yours being from the 40's and not having any significant damage in good condition I would give it more value with the USMC engraving and less value because of the rotary change valve (instead of the old Schmidt piston change valve). I would estimate between $900 - $1600.