upper markings

[spittoon]

well i got a "dmps upper " dose any body know markings forward of the front sight it is marked "M1S" AND UNDER THAT "SS" I KNOW IT IS STAINLESS STEEL BARREL BUT WHAT IS THE M 1 S MEAN THANKS

[mc223]

Model 1 Sales

[legaleagle]

+1 on the model 1 sales

the DPMS barrels I have seen have the DPMS letters on the bottom of the barrell in front of the FSB.