I just mounted my ARMS 51 on my Bushy A2.  I noticed the handguard cap rubs on the ARMS 51.  Nine O'Clock position.  Does anyone out there have the same problem?  I'm not going to use the standard handguards, so I clearanced (bent) the cap to clear the ARMS 51.  I know that ARMS makes quality products, could this be caused by the Bushy A2 upper?  When mounted on a different A2, Bushy, it still rubbed.  I also have an ARMS 39, and when mounted on my A2 it does not line up with the front sight tower.  I don't believe that ARMS would send me 2 different mounts that were both out of spec.  Thanks for any help.

I had the same problem, and posted a reply detailing how I worked this situation in your thread in the Optics section.


Chris

Please send me some pictures close ups of your set ups,Im thinking of setting my new project up like this.Is it heavy?

Dont feel bad, I put a RAS 2 on my 16" bushmaster upper and the front hand guard caps and the front of the RAS2 has a 3/16 to a 1/4"gap,not much to worry about,but this is my pride n joy,but what are you going do?

I have seen carry handles from Colt slightly out of alignment, I have seen barrels from various makers out of alighnment, so it's anyones guess why it hits the cap a bit. Let us all know how it shoots with the optic way out there compaired to the irons.
Good shootin, Jack

I have the HBAR and with the 51  it is heavy.  I'm running the aimpoint M2 and the arms 22m68.  I havent been to the range yet, but I used to have the arms 39, and really liked the way it shot.  I'll post some pics as soon as I can, including the nearly folded handguard cap.

I have seen a #51 that was tightened too much where the cross bar is. Try re installing and do not tighten that lower front cross bar so much. DO IT NOW!:-)
Jack

I just removed and reinstalled my 51.  Even with the front crossbar loose, it still is misaligned.  I'm not too concerned, my #39 used to do the same thing.  One quick question, do I really need to loctite the barrel yoke screws?  I used the loctite on the initial install, should I go back and re loctite them?  Thanks for the info.

I would loctite all screws on the SIR.

On my #45 I skipped loctite on the barrel clamp screws, and they came loose.


Chris

[img]http://www.imagestation.com/picture/sraid60/pca64a97d1d111fe6ef96f8b690497b27/fc404f62.jpg[/img]

You'll notice the weight difference between the HBAR and M4 barrels, that's for sure.


Chris

I posted pictures of the modification I did on my #51 here:

[url]www.ar15.com/forums/topic.html?b=3&f=18&t=172822&page=1[/url]


Chris

My #51 was straight with the crossbar was loose, then the front end would move to the right as you tighted down on the crossbar.

Drove me f*%kin' NUTS!


Chris

"Dont feel bad, I put a RAS 2 on my 16" bushmaster upper and the front hand guard caps and the front of the RAS2 has a 3/16 to a 1/4"gap,not much to worry about,but this is my pride n joy,but what are you going do?"


[b]No offense but that was exactly the way the KAC product was designed to mount (with a gap although your gap may be excessive). The gap on mine was about 1/16in and it was a Bushy too. It has to have a gap to free-float the barrel.  If your gap is really 3/16in to 1/4 in you probably have an out of spec barrel. The RAS's are all the same size. KAC quality control is better than BM[/b]

My ARMS #45 did the same thing. (I took a dremel to the front of the SIR and removed about .050in of material and then it floated.) My gun shot horrible untill I fixed that (like 2MOA at 100yds.) After the fix it shot 1/2MOA.