I have noticed that ammunition for the MX-line of rifles is not compatible with the Tavor line. I understand both weapons use different magazines, but both rifles are chambered in 6.5x39mm. Therefore, the magazine well on an MX should be perfectly capable of accepting 30 round 6.5mm magazines from the Tavor, just as the Tavor should be able to accept 30 round 6.5mm STANAG magazines.
I think this would add an element to the game which I remember Arma 2 has already. Ammunition from different weapons chambered for similar cartridges could be scavenged from corpses to allow players and AI to stay in the fight longer.
In addition, in Arma 2, for some reason suppressed weapons were capable of using standard magazines as well as magazines with the SD tag, while unsilenced weapons were not capable of using silenced ammunition. This doesn't make sense. Generally speaking, the ammunition used is one and the same.
Of course, in the case of rifles, supersonic rounds make silencers less effective. So, I suppose SD ammunition might be intended to represent sub-sonic rounds, which makes sense. However, this does not explain why SD magazines are exclusive to silenced weapons.
Please fix the first issue mentioned, and please avoid the second.