I have a BM M4 with the fixed carry handle. I bought a KAC RAS and have attached an Aimpoint Comp M2 and vertical grip to it. Didn't buy the FF RAS bacause I have a KKF A3 TacBrake permanently attached which would have made the installation of the FF RAS more time consuming and more costly (because of the required removal of the brake) and I don't like goosenecks. That said, I am very, very please with this setup.

I fully agree that mounting optics to the receiver is the preferred way to go. I have found that the accuracy of my Aimpoint has not been greatly affected by being placed on the RAS. Just a month or so ago I went to the range and fired over 500 rounds to specifically test for any changes in accuracy. Using the Aimpoint at 50 yds with the gun good and hot, I noticed no significant changes to my zero.

For those of you with the same set-up as me, have you noticed the same thing? At some point on AR-15.com awhile back, a KAC rep. made the case as to why the RAS was a fine platform to mount an optic to. Several search attempts have been unsuccessful to find the discussion but between his description, the patent of the RAS and my personal experiences it seems to be okay.

I want to hear some other expereinces, input from those of you out there. Again, I should have gotten a flattop and all of my concerns would be a moot point but I didn't...  

I had the same set up for a while.  No problems at all.  I think any dispersion due to the RAS moving is less thna the 4 MOA dot.

I had a Trijicon Reflex mounted on my RAS for years with NO problems.  It was a 200 yard max set up, so any slight variations in consistency mounting on the forearm might have had were a non-point.

Its not ideal, but its doable, despite claims otherwise from people regurgitating what others have said.

Yes sir, Lumpy is right, the difference is in long range shooting.  

I think a lot of the confusion comes from the RAS v. RIS.  RAS is substantially more stable.  I could never make mine budge even a millimeter once it was locked on, zero play.  The same is not true of the RIS.

Actually, I had an AImpoint 5000 on a RIS in a KAC mount, that tells you how long ago I tried this.  Again, no problem even w./ the RIS.  I agree that the RAS is the more stable platform of the two.

Aimpoint [b]4 MOA[/b] dot.

Lets say a loose RAS gave you 1/2 MOA variation in any direction.

At 100 yards its going to be insignificant.

Was there any issues with mounting other items on the RAS and it holding zero?  I am looking at puting a foregrip, light, and (hopefully) OTAL on it.  I even want to mount the sling on the RAS w/ a QD.  I like the RAS, but was concerned about the above issues causing problems with sight zero?  It would seem to be more of an issue with full auto/heat than with semi-autos.  I like the RAS (IMHO) as it seems more suited for the EOTech and is more handy swapping Aimpoints and EOTechs (no hump).

I probably would've mounted optics on my RAS, but it was rotated slightly off-center.  When I had my Reflex mounted, the front sight post was canted in the field of view.

I stuck with a carry handle mount, until the #51 SIR came along:

[img]http://www.imagestation.com/picture/sraid60/pa800570d6f74006cff35bb8cc53e60b4/fc404f59.jpg[/img]

I don't worry about sight zero, heat from the barrel, attaching a sling, etc.

It's around $60 more than a RAS, and well worth the money.  


Chris

I think we just covered that...

I got that there were some reservations about mounting forward, especially at long distances. I saw people saying that they mounted sights on the RIS and RAS and not having problems.

TS

[url]http://www.ar15.com/forums/topic.html?b=3&f=18&t=164329&w=searchPop[/url]

Coldblue is ... um ... knowledgeable about such things.