TRG-21 & TRG-20, Iron sights are not aligned with the sights, I don't know this was done on purpose, but even the 2x Scopes such as MRCO and ARCO etc... are off alignment in the TRG family.
Also the Mk 20 Iron Sights are not aligned, but with Optics it's good.
The Sting 9mm also shoots above it's Iron sigh, Optics are ok.