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6/20/2004 12:07:13 PM EDT
I'm trying to install an ARMS SIR on an Armalite AR10 carbine.  Already removed the handguard cap, delta ring and related parts.  I now have 2 problems.  

First, the SIR system is canted to the ejection port side when I slide it on the upper receiver.  I can't find any burrs or other issues that would cause this.  The second problem is that the SIR will not slide back far enough on the receiver to attach the yoke around the barrel nut.  

Anybody else have issues with this combination?  I think the inside of the SIR is cut incorrectly, as I can see where it is hitting on the receiver when I slide it onto the flattop.  I am planning on calling ARMS tomorrow, but until then I'm looking to see if anybody else has run into similar issues.
Thanks
Scott
6/20/2004 5:56:44 PM EDT
[#1]
Is it the right part # ? Maybe NewARguy can help.
6/20/2004 6:07:37 PM EDT
[#2]
I would post this in two places
ar10 forum
armalite forum

In fact I was going to move it to AR10 but figured it was not my place to do so.

6/20/2004 6:45:11 PM EDT
[#3]
It does appear to be the right part number, #53 AR-10 Carbine S.I.R. Model M.  Even says AR-10 on the box.  Anything is possible though.

Aimless,
Didn't think about the Armalite section, but was trying to minimize posts and maximize foot traffic.  I'll try the AR10 section.  
Thanks
Scott
6/20/2004 7:45:13 PM EDT
[#4]
I dont know if this is the same as another post I recall, but I swear, I recall reading a long post where a guy was having a similar problem. There is a small ledge on the inside of the SIR that seat around the forward section of the uppers flat top rail. If the flat top rail is slightly out of spec, this is what happens. The SIR wont seat back fully on the rail. Like I said, I dont know if this is what is happening to you, but the problem sounds similar. As I recall, the person having the problem then took off the tiniest bit og material from whatever edge it was on his upper and the SIR fit right on, no problem. Anyone else remember this thread?
6/20/2004 8:00:56 PM EDT
[#5]

Quoted:
I dont know if this is the same as another post I recall, but I swear, I recall reading a long post where a guy was having a similar problem. There is a small ledge on the inside of the SIR that seat around the forward section of the uppers flat top rail. If the flat top rail is slightly out of spec, this is what happens. The SIR wont seat back fully on the rail. Like I said, I dont know if this is what is happening to you, but the problem sounds similar. As I recall, the person having the problem then took off the tiniest bit og material from whatever edge it was on his upper and the SIR fit right on, no problem. Anyone else remember this thread?



Yep, it was about 6 months ago. It was on either an Armalite or RRA, IIRC...

-Cap'n
6/20/2004 8:21:34 PM EDT
[#6]
Thanks guys.  I was afraid this might be your answer.  I think there might be an issue with the upper and the SIR, but I'll have to work with it some more.  If anybody finds more info or a link on the previous post, please let me know.
Thanks
Scott
6/20/2004 9:40:23 PM EDT
[#7]
Actually, I could have sworn it was a PWA upper, but its too long ago for me to really recall.
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