'75 Schwinn Paramount P-10, '86 Ritchey Commando, '87 Schwinn Cimarron, '91 Trek 990, '87 Schwinn High Sierra, '73 Schwinn Super Sport, '4? Schwinn New World, '76 Swing Bike.
What is the wheel size? If 650c it could be the indicator of this vs. the standard road frame 'K' (the first letter being the fork size), before the switch to the first letter to designate the frame type and the second to indicate the company.
700c, yea I had not thought of wheel size. The waterford site was somewhat helpful but didn't specifically address "M", or other letters preceding the waterford plant "W" other than the fork length letter.