gorelicks...anyone....questions about my new upper?!?!?!

[dsg2003gt]

I just bought this new upper, it is a RRA midlength, with a DD rifle rail installed.

Taking a close look at it while comparing it to my other rock river, I found that it has this stamp/print mark on it:
http://www.speedoptions.com/members/129233/41488/pic6.jpg
whereas my other rock river has nothing there.
Also, when looking at the feed ramps(milled into the upper, the midlength looks like they were dremeled, whereas my original looks like they were cnc cut.

original:
http://www.speedoptions.com/members/129233/41488/pic7.jpg

and the midlength:
http://www.speedoptions.com/members/129233/41488/pic9.jpg

http://www.speedoptions.com/members/129233/41488/pic8.jpg

any comments appreciated!
Thanks
Matt

[Big Bird]

By no means am I an expert. But I have a pair of CMT uppers with M4 feed ramps cut at the factory (in fact one is stamped M4 above the gas tube hole)...in neither case are the feed ramps as big as yours and in both cases my feed ramps in the receiver are anodized...not bright....

M4 feed ramps aren't necessary in a semi-auto gun... They only affect a full auto.

Yours look to be aftermarket cuts...not original factory. But I could be wrong.

[RMTactical]

The "keyhole" is normal. I have a RRA upper with the same marking, and I also have a CMT upper with an "A" on it. It's a non-issue.

I don't know what to tell you. I don't know enough about the sitution and I'd probably need to take a close up look to find out what's up.

[Sierra]

Have you called RRA? They ought to be able to explain it.

[Big Bird]

The keyhole is the mark of Cerro Fabricated Products...they are one of a number of suppliers of forged uppers for Colt, FN and others. The funky looking "A" is from Anchor Harvey Aluminum, there is another that looks like the outline of a birds head...its from Cardinal Forge...

All are sub-contractors and supply receivers to the military through the manufacturers.

[dsg2003gt]

thanks guys! I referenced the stamping on ar15.com and you are correct, that it is cerro.

The feedramps are not really a big deal, I just thought it was a cheaper(no-name) upper receiver and it was not a rock river, and that the feedramps were an identifying mark.

But since the keyhole is normal, and (all) rock river feedramps are dremeled in, that is fine.

Ill have pics of the whole upper up laber.

Thanks guys!
Matt