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-   -   Upper receiver marks (http://www.firearmstalk.com/forums/f20/upper-receiver-marks-29330/)

EW1066 07-14-2010 09:01 PM

Upper receiver marks
 
This may seem silly to some but my curiosity is killing me. On the left side of all cast and forged uppers ( that I have seen )there is an embossment that coincides with the recess were the cam pin is when the BCG is closed. On that embossment on the outside of the receiver there is a .250 vertical line. Does anyone know the purpose or meaning of this line. I cant seem to find an answer with the search function. And like I said its just bugging the dog crap out of me. Everything else on this gun has function and meaning....except this little line. I'm getting close to losing sleep on this one. I sometimes will fixate and obsess over something like this. Right now it's just fixation. Please help me !

Thanks in advance.

Vince

EW1066 07-15-2010 03:55 AM

Would I be correct in assuming that no one here knows either? Well, I guess I don't feel so bad. It's still gonna bug me though.

I'm still open to an answer if anyone has one.


Vince

willfully armed 07-15-2010 04:09 AM

give up a pic man!


One second thought, its likely a reference point for an optic.

EW1066 07-15-2010 04:19 AM

http://i278.photobucket.com/albums/k.../ari5upper.png

Okay maybe this will help.

Vince

Jpyle 07-15-2010 04:24 AM

Quote:

Originally Posted by EW1066 (Post 315236)
Would I be correct in assuming that no one here knows either? Well, I guess I don't feel so bad. It's still gonna bug me though.

I'm still open to an answer if anyone has one.


Vince

With no first hand knowledge my guess would be that it is a registration mark to establish a zero point for all future measurements during the machining process similar to those found on multi-color print work.


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