Quote History Quoted:
I picked up a 6720 a couple of days ago. The barrel has a w near the barrel nut with a date code of 12/15 and the standard C MP markings at the top. The stock has two numbers molded into it. 13629 and 4U486. The charging handle has 13629 stamped on the bottom of the T.
The bag was stamped January of 2016.
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The cage code 13629 belongs to Colt Defense, and 4U486 belongs to P&S Products which currently supplies Colt's production furniture, they started to add these cage codes about the last quarter of last year.
It's good that Colt are now stamping also the charging handles to easily identify them, before they're impossible to identify as a Colt part.
Another part that Colt needs to identify are their detachable carry handles.
Ref:
http://www.armyproperty.com/manufacturer/4U486