Well if you read the info you'll relize that this weapon comes in several different versions with inter-changable parts. One chambers the standard 5.56mm NATO round used by the M-16. Another version uses the 7.62 mm round used by the M-14, other versions are desinged to chamber standard Russian rounds like 5.54 mm. all the parts like handles, sights, buttstocks, etc. are completely inter-changable. I think this gun would work really well with JAM.