It may have been knocking around for a while now but ive just been showed a little bit of info on some rifle the septics are using or being offered called the IAR. pretty much an M4 but when you stick it on auto it fires from an open bolt. it uses the standard 30 round mags. Its being posted as a replacement for the minimi( the m249 or whatever they call it) but wouldnt this just make it like the LSW ie a pain in the arse to change the barrel and having to reload every minute??