Try laying on your side and propping the bolt knob of a SCAR on a burm and firing it while you are under fire.
Under fire? Was this live action or SIM?
Bolt knob can be switched to the other side in less than 5 seconds. Which in an actual gun battle may be irrelevant but if that's the only draw back. I'll still roll with it. I'm an admitted FN fanboy though so I'm very biased. I must say I also thoroughly enjoy HK as well though.