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Posted: 10/30/2009 6:25:58 AM EDT
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I have this sp1 upper that has the 'off set' forging under the ejection port, and the big hole pivot, thought it unusual, as my sp1 from about 1978 does not have it. With my lack of 'upper' knowledge it my not be unusual :O)
See the pictures, any comments, date suggestions, uses...R6001 ??? 
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Looks like the "CM" forge code uppers started showing up on the SP1 around '77 or so.
Lots of good SP1 info here: SP1 Data Base |
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