OK, I am getting conflicting reports, so if anyone actually HAS YOUR HANDS ON ONE, please comment. I have NOT been able to get my hands on one yet.
CHARGING HANDLE
Does the SCAR 20 have the same reciprocating charging handle as the SCAR 17?
Looking at pics, it appears that is the case, but people have tried to tell me that it is NOT the case.
If it does, per the earlier comments, it is something that you really need to be aware of.
UPPER RECEIVER DESIGN
This is going to take some serious knowledge or experience to answer this one, but did they make any changes to the Upper Receiver between the Mil MK20 and the Civilian SCAR 20?
I suspect the answer is NO, and if that is the case, it once again is an issue that people need to be aware of. People need to be aware of it because of the previously mentioned issues with optics and accessories. There is the recoil/return to battery forces (recognized by NSW/Crane), but IMHO there is also another issue. If you have been around one being shot, the Upper Receiver can "sing like a tuning fork".
Listen closely in this video and you will hear it:
It vibrates and resonates, which IMHO can also cause issues with things that are mounted to the Upper. I suspect that the longer design of the SCAR 20 forend, may amplify this even more.
Any feedback on those SCAR 20 design elements would be greatly appreciated!
*EDIT
Per the pic below, taken from FN's website.
Charging Handle - looks the exact same.
Upper Receiver - interestingly, the SCAR 20 has 2 additional screws/bolts right behind the gas block in the Upper Receiver that the MK 20 does NOT have. Not sure what the story is on this?