Request advice: Mounting RDS, Magnifier and Back-up Iron Sights

#1
Hello,

I am writing concerning a question about the "optimal" mounting of an RDS, Magnifier and back-up iron sight.


background info:
  • The RDS has 3 "tabs", the 2 outer "tabs" are fixed. The middle "tab" is connected with a screw and the usual "clamp" (as shown in picture 1). Bild 1.JPG
  • I have 2 options with this setup, each with disadvantages:

Option A (as shown in picture 2):
  • The front part of the "clamp" for fixing the RDS touches the front hand guard
  • The front "tab" of the RDS touches the first "tab" of the Picatinny rail of the hand guard Option A Bild 2.JPG


Option B (see picture 3):
  • The RDS contacts the Magnifier
  • The "clamp" touches the front hand guard only slightly
  • The "tabs" only slightly touch the Picatinny rail of the upper
Option B Bild 3.JPG
I hope the explanation is easy to understand, despite the roughly chosen terms (I am not a native speaker).

Questions which I´ve been asking myself:
  • Are zero shifts or damage/greater wear and tear to be expected here?
  • Would you recommend one of the mounting options or do I have to get other components (Eotech instead of the existing sig-optics etc.) so that it fits
  • Should I just move magnifier and RDS to the back and remove the back-up sights?
Thanks and best regards
 

Default.mp3

Regular Member
#2
Could try an Aimpoint Micro/CompM5, would definitely fit on the receiver without impinging on the handguard nor the magnifier. You might also look into getting shorter rear sights, the H&K one seems to be much longer than something like a Magpul MBUS Pro or KAC Micro, though I don't know if those would be available for you overseas, nor would they work if you're utilizing the gas block mounted front sights, due to the added receiver height.
 
#3
My experience with HK416 says you're good to go with option A. I've seen enough operators with their M4 or T2 placed entirely on the handguard without issues. Most guys I know, including myself use option A.
 

shoobe01

Regular Member
#4
Agree with BenNL. I know people who actually jumped out of airplanes, etc with sights on just the front rail.

For mostly legacy reasons when I ran a different magnifier setup thingy, my RDS with similar size and cross-lugs is forward like A, about 1/3rd on the front rail. If I logic it out, I like that the sight helps clamp the rail down to be sure it doesn't move, since I also have a laser up there. Not sure it helps, but nothing (on several guns set up like this) has been a problem for me, for a long while.

Now... my magnifier has the more typical clamp to the front, so the rear sight is all the way back, and if needed (it never is) you just flip the magnifier right and the sight can pop up.
 

shoobe01

Regular Member
#5
Oops, missed the edit window with sudden diaper changing. Bottom two are examples of things I've run forever, banging around in the woods, immersed in creeks, and more. The bottom one has more rail engaged as I used to run a multiflex and put a NOD back there but do not, but the gun works so why change it.

The 12.5" gun does point to another thing where I put the front sight rear of the laser, because irons are less important, so I am happy to give up sight radius for a cleaner laser, better position. I think rears can't be moved or the aperature won't work, but fronts can be pretty much anywhere.

I like (have used) the irons on the issue ACOG models, wish more RDS came with emergency BUIS.

(Top most is 9mm training upper, RDS same place despite no need for consistency. Other is a .300 as a minisniper).
 
#6
Nice collection.

Thanks for the advice; I´m going with option A then but will sort the components out (different RDS or BUIS) in the long run.
I´m still a bit hesitant however, since I fear the mount of the RDS might become damaged over time from differing recoil impulses by the handguard and the receiver.
 

shoobe01

Regular Member
#7
I don't think I follow "differing recoil impulses."

If your forearm rail flexes that much: get a different rail. If it's at all attached well, it will have very, very little motion at the receiver end, and you just clamped a sight that holds the two together. It should behave as a unitary system, no problems at all.
 
#8
HK 416 has a good lockup between handguard and upper. The lug that couples the handguard to the upper does a great job keeping everything in line
 
#9
Just adding to be sure: It´s not a 416 but an MR223 with slimline handguard (whereas the 416 has a quadrail handguard).
I don´t know if there are any differences in the lug resp. strength of the connection.
 

shoobe01

Regular Member
#10
I am sure it's very solid, but... just thought of something else for this entire weapon series. Piston operated guns. You need to maintain the piston periodically. So, you need to remove the handguard to do that.

Does this happen? Does everyone regularly remove the rail/handguard, meaning they dismount their sights and re-zero everything all the time, or is the rail/handguard so good it returns to zero or... what?
 
#11
With the 416's I've never noticed issues concerning zero. Depending on the mount it, shouldn't be. If the front lug locks into a slot on the handguard, that would mean you need to remove your sight when you clean the gas system. A check zero after removing your sight is always advisable.
 
#12
I am sure it's very solid, but... just thought of something else for this entire weapon series. Piston operated guns. You need to maintain the piston periodically. So, you need to remove the handguard to do that.

Does this happen? Does everyone regularly remove the rail/handguard, meaning they dismount their sights and re-zero everything all the time, or is the rail/handguard so good it returns to zero or... what?
I hardly ever remove the rail for piston maintenance.
When I did, after approx. 1000 rounds it was still in good condition.

Either way, I am going to test it and report back.

BenNL, it doesn´t really lock into the lug of the handguard, but the front lug of the RDS is pressed against the first lug of the handguard. It "sits" right in the space between the last lug of the upper and the first lug of the handguard.
Removal of the RDS is however necessary because the left side of the RDS "clamps" along the upper and the first 2 cm of the handguard.
 
#13
On a side note:
I found target acquisition at short range considerably faster with the RDS as far back to the eye as possible.

Might be because I am left eye dominant but right handed (therefore shooting the rifle right handed and looking through the sights with the right eye)...