Exhibit A: The BAS Ranger/Delta addon, otherwise in all manners of speaking an excellently well done piece of work. But the unsilenced M4's and the silenced M4's have different magazines (M4 Mag and M4S Mag). Considering there already IS an M4 mag available in the original game... *sigh*
There is not already an M4 mag ingame, there is an XM-177E2 magazine, if we had used that magazine it would say "XM-177E2 Single" or "XM-177E2 Auto" when using an M4A1 (Despite looking similar they are different weapons), you also can not fit a silenced weapon with a normal magazine because it wont be silenced, the ammuniton and sound information are in the magazine, so not only would it sound like a normal weapon, the ai wouldnt regard it as silenced either, also, most ammuntion used in silenced weapons is subsonic ammunition, otherwise it is not silenced, just muffled, as the bullet will still have the supersonic 'Crack' as it leaves the barrel. So realisticly you wouldnt use unsilenced ammunition in a silenced rifle, or silenced ammunition in a normal rifle.
What JAM is doing is creating magazines that have better sounds, and are suitable for any weapon of the same caliber, that uses the same ammunition (ie non silenced), we will also be creating high dispersion versions (as seen in the nam pack) of every magazine included, the one problem we have faced however is that there will no longer be "M4 Single" or "M4 Auto", as this information is in the magazine, not the weapon itself, so we will either have to change it to "Rifle Single" or "5.56x45mm Single" so that it will be able to be used in all the weapons that realisticly can use that magazine without having "M4 Auto" in the top left corner when firing an SA-80. It will however still say, for example, "Pick up SA-80", or "Weapon SA-80"
There are many flaws with the way BIS made the ammunition and magazine/weapons cpp's, the way JAM will do it is the easiest way to deal with them, also, with a hell of a lot of addon makers ready to be JAM compliant you wont have to dig through pbo's looking for various classnames for magazines, you will only need to have the JAM readme/ammunition list that will come with the addon.