The CQ 311 is a copy of the "old" M16, has a 20 inch barrel, ugly furniture & a 1 in 12 twist... And had a "painted" finish on the receiver...
The CQ-A-1 5.56 is a copy of the more recent US M4, has a 14.5 inch barrel, much nicer furniture & a 1 in 9 twist... Not to mention a decent finish on the receiver...
Others will be able to chime in with more...
Cheers
Jay