At long range, the RCO optic is only accurate on the MX or MX3GL rifles

https://www.youtube.com/watch?v=hJ07gkvcBME

I had been missing long shots using an MXM with an RCO.  Finally, I spent some time at 'the range' and found out why...

The MXM, MX SW and MXC are all inaccurate above 500m when using an RCO.