you got it all wrong its >armalite ar15>601>602(XM16)>603(XM16E1)>604(M16)>614(M16A1)
Did Armalite actually manufacture any AR-15’s for sale? Or just make prototypes?
My understanding was Colt manufactured all the AR-15/M16’s and that Colt made them at first with a 1:14 twist and that is what Malaysia got in 1959 from Colt. And that when the XM16’s first went to Vietnam they were 1:14 as well. Based on real world results in Vietnam I thought the decision to go to a 1:12 for M16 was made for the Military contract.
There seems to be a lot of gray areas or redacted information that leaves a lot of questions about somethings. Even books on the AR-15/M16 I read years ago had different information.