[Montrala]

This hand guard is for HK416A5 that has adjustable gas block with settings for "Normal" and "Suppressed". Those marks help to see what position is selected.

You can see it on my photos here: Montrala: HK416A5 - newest evolution of famous assault rifle (pictures 10 and 11)

 

[Montrala]

Gen 1 AGR that required use or allen wrench was in fact quick fix when out of the blue Norway requested that they can't live without one. HK quickly modified existing gas block to accommodate this. Then they went back to drawing board and after several years came back with proper AGR in HK416A5. Meanwhile Norway decided to get rid of AGR because it introduced more problems that it solved (actually in first place they wanted it, because proper piston rifle must have AGR, not that they had any real reason to use it). Whole story.

 

[Montrala]

In case of G3Kurz it is actual knowledge, in my case it is just analytical skill and putting small bits of info found here and there together.

So in case of conflicting info G3Kurz beats Montrala all the time