'jwagar' - Perhaps another KCA member will be kind enough to check if your serial number, 16720, appears in the SRS data.

Likely, a better source of information (than contacting Springfield Research Services) would be for you to purchase Joe Farmer's Book (listed in KCA 'classifieds'). This will open access to his site.

Contacting 5MadFarmers (Joe Farmer) would be a good step. He may have an 'outside the box' explanation for your questionable "carbine".

p.s. Don't mention my name, it will impede having a good relationship with Mr. Farmer.