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1/18/2013 11:53:04 AM EDT
Hey guys,

I have a brand new never fired Rock River lar15. I am having some problems getting the bolt to be pulled back far enough with the charging handle. I tried it with various mags and the  bolt catch button. I feel like the shop I bought it from may have pieced the upper and lower together before selling it to be. The upper is a carbine length if that matters. It has a pinned stock. What can I check out?

Thanks
1/18/2013 12:50:11 PM EDT
[#1]
Best bet, the wrong buffer and buffer spring in play.

Pull the buffer and buffer spring, then measure the distance of the void in the tube (receiver extension depth) then get back to us with that, the free length of the buffer spring, and the length of the buffer..

Normally when dealing with factory pinned carbine butt stocks, they are based off of standard receiver extension tube depths, but if the stock was after market pin (started out at a telescoping stock), then it would use the shorter carbine buffer and carbine length recoil spring.

Also, could be that your stock used a butt stock bolt (in the back end to hold the stock to the tube), and although the buffer and spring are the correct length, the screw installed is too long, and now protruding into the back of the tube void instead to limit the depth that the buffer can recess into it.

Lastly, could be that the entire butt stock is an airsoft knock off, and was not receiver extension depth correct from the start.
1/19/2013 6:32:42 AM EDT
[#2]
I know that with the bushmaster pinned collaspable style stocks, they are a rifle length receiver extension and use


a rifle length buffer and rifle length spring.





Also, where the lever and pin assembly is on a real collaspable stock, bushmaster uses an Allen head bolt.





That Allen head bolt holds on the faux lever, but there is a hole drilled in the receiver extension where that Allen head bolt goes


and the problem is if you thread/tighten it in to far the Allen head bolt will protrude thru the hole into the receiver extension enough to interfere


with the buffer assembly.





You can tell if you have a bushmaster pinned stock by checking to see if your stock has the bushmaster logo on it.

 
1/20/2013 4:18:14 PM EDT
[#3]
0
Quoted:
Best bet, the wrong buffer and buffer spring in play.

Pull the buffer and buffer spring, then measure the distance of the void in the tube (receiver extension depth) then get back to us with that, the free length of the buffer spring, and the length of the buffer..

Normally when dealing with factory pinned carbine butt stocks, they are based off of standard receiver extension tube depths, but if the stock was after market pin (started out at a telescoping stock), then it would use the shorter carbine buffer and carbine length recoil spring.

Also, could be that your stock used a butt stock bolt (in the back end to hold the stock to the tube), and although the buffer and spring are the correct length, the screw installed is too long, and now protruding into the back of the tube void instead to limit the depth that the buffer can recess into it.

Lastly, could be that the entire butt stock is an airsoft knock off, and was not receiver extension depth correct from the start.






ok just got some measurements. The void in the stock is 6 3/4", the spring is 11" and the buffer is 3 1/4" from end to end (including the bumper)

The stock has no markings on it, but was a 6 position that was pinned.

Any ideas?
1/20/2013 5:11:00 PM EDT
[#4]
Tube depth is 7" .
1/20/2013 5:15:26 PM EDT
[#5]
mine is 6 3/4" up to the detent  pin
1/20/2013 5:32:19 PM EDT
[#6]
My LMT mil-spec receiver extension is 7"in. in length on the inside



my LMT spring is 10 3/4"in. long



My LMT H buffer is 3 1/4" long



If your receiver extension is 6 3/4" long it is too short.



When you pull the bolt carrier back as far as you can, how far away is it from

reaching the back of the bolt catch.



If it's a quarter inch then you know it's you receiver extension that is too short and needs to be replaced.
1/20/2013 5:33:27 PM EDT
[#7]
There was a company that sold some that were shallow. Caused the bolt face not to catch on the bolt catch.
1/20/2013 7:29:47 PM EDT
[#8]
Sounds like your buffer tube is too short.

You may want to contact RRA with the serial number and see if your "complete" rifle was built from a stripped lower.

1/23/2013 6:41:50 PM EDT
[#9]
Quoted:
Sounds like your buffer tube is too short.

You may want to contact RRA with the serial number and see if your "complete" rifle was built from a stripped lower.



i tried to call for 3 weeks before i bought it but had to act fast because of the ny ban.
1/23/2013 8:57:41 PM EDT
[#10]
Quoted:
Quoted:
Sounds like your buffer tube is too short.

You may want to contact RRA with the serial number and see if your "complete" rifle was built from a stripped lower.



i tried to call for 3 weeks before i bought it but had to act fast because of the ny ban.


You could try posting in their industry forum here, they monitor it regularly.

http://www.ar15.com/forums/f_2/38_General_Discussions.html
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