2slow

AR15 was originally made by ArmaLite Rifle, thus AR, only semi-auto action, the design was later sold to COLT and eventually designated as M16 by US Govt, burst/Full auto version available
Colt later selling semi-auto Civilian version as AR15

M4, however is a shorter and lighter variant of the M16A2, as I know it's Colt project XM4
M4 only have semi/burst, while M4A1 have semi/full auto feature

anyway, they are all derived from Eugene Stoner's AR10,  they're all gas-operated, magazine-fed, using 5.56mm NATO round

有錯請大家補充

2slow

引用:

原帖由 Tekkno 於 14-6-2013 15:06 發表

M4/M16 is the U.S military service select fire assault rifle
AR-15 could be either the original M16(M601????) not too sure. or commonly known as a modern semi-automatic civilian sporting rifle. ( N ...

you are right, 601 is Colt's model number for AR-15
M16 is model 604