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12/1/2009 2:57:52 PM EDT
Ok, so I just got my KAC RAS and I went to install it and it seems to bind in the front above the gas tube.  I have an A2 front sight post on a RRA Lightweight R4 profiled 1:7" twist barrel.  I was wondering if anyone else has had issues with this.  I know how the leaf spring is supposed to be installed and I do this all the time with my service weapon, as my unit is currently issued the RAS.  Anyone have any thoughts or ideas?  It seems to be binding on the metal piece that houses the leaf spring.  That seems to be held in place by a single roll pin.  I can take this piece out and the RAS slides right into place and locks with the rear locking mechanism however it isn't as secure as it would be with the leaf spring in place.  Modify the metal plate that holds the leaf spring in with my dremel?  

Thoughts, ideas, and similar stories welcome here.

Airborne!
12/1/2009 3:37:47 PM EDT
[#1]
Not sure if this will be any help or not

link
http://www.quarterbore.com/kac/kacrisras.html

Cut and paste from above link


The RAS also has a tighter profile at the front sight that limits the use of the RAS to barrels that measure 0.835" - 0.855" diameter just after the front sight tower.
12/1/2009 3:39:25 PM EDT
[#2]
Also a link to the instructions


http://www.quarterbore.com/library/pdf_files/kac_ras_inst.pdf
12/1/2009 4:00:17 PM EDT
[#3]
You might just need to apply a little more force to push it over the gas tube. I've had a couple that were a little tight slipping over it before.
12/2/2009 5:06:17 AM EDT
[#4]
Thanks, guys.  When I get off today I'll take a set of calipers to the barrel and see if it's the right size.  I was looking at my M4 and it looks like the barrel is thinner than the AR15 that I'm building at my house.  Time to improvise, I'd say.  

Again thanks for the links.
12/2/2009 5:35:45 AM EDT
[#5]
You're on the right track. I thought I had an issue with my M5 RAS b/c I thought I had an HBAR, but it's just gov't contour. The rail wont fit an HBAR and it required a little bit of force to seat it on my barrel which is a RR 1:9
12/2/2009 11:44:05 AM EDT
[#6]
God I hated putting mine on.... Hell is a word to think of.
12/3/2009 5:59:01 AM EDT
[#7]
Alright, so last night I fitted the RAS in.  I found that it needed to be 0.02" larger of an opening.  So I broke out the fine grit barrel on my dremmel and increased the radius on the handguard spring retainer.  This part is pinned into the hand guard and I figured if I messed it up, I can just pin a new one in.  however through some patience I got her together last night.  Looks great.  Put my magpul rail covers on.  I'm pleased, it's a nice fit with no play on the RAS at all.  Thanks for the input, gents.  I took some pics last night, if I can get my wife to email them, I'll post some up later on.  I took the pics against my body armor so I could see the flat dark earth, and it does well to conceal the weapon a bit.  Over all, again, i'm very please.
12/3/2009 10:36:00 AM EDT
[#8]
As promised:

http://farm3.static.flickr.com/2485/4155534779_8a2a67863e_o.jpg
KAC RAS that gave me so much hassle!  With Magpul FDE rail covers.  I like the thinner profile that they create over the KAC covers.  

http://farm3.static.flickr.com/2662/4156296898_b727bacf58_o.jpg
In front of my body armor.  I think the FDE does a good job of blending with the ACU pattern.

Just ordered the BUIS yesterday.... almost ready to finally test this build.
12/3/2009 3:02:54 PM EDT
[#9]
please take a pic of the aarea you had to open up/


Thanks
USAGOLD
12/4/2009 9:16:36 AM EDT
[#10]
Alright, let me talk myself into taking it off tonight when i get back home.  No fun in that.
12/5/2009 2:29:42 AM EDT
[#11]
That would be a big help/

Thanks
USAGOLD

12/5/2009 2:40:13 AM EDT
[#12]
Quoted:
You might just need to apply a little more force to push it over the gas tube. I've had a couple that were a little tight slipping over it before.


This. Just give it a little tap while holding back the delta ring.
1/5/2010 7:10:37 AM EDT
[#13]
This isn't my rifle, but another KAC rail.  I just wanted to document what I did without taking it all apart just yet.  Happy new year all.  Sorry it took so long to post up a reply.

http://farm5.static.flickr.com/4027/4248421794_5e966d22b6_o.jpg

http://farm5.static.flickr.com/4054/4248421836_40e7162221_o.jpg
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