Here's how your description.ext should look like:
class CfgMusic
{
tracks[]=
{
mguns, rifle1, mgun_burst1, mgun_burst2, mgun_burst3, mgun_burst4
};
class mguns
{
name = "mguns";
sound[] = {"\music\mguns.ogg", db+10, 1.0};
};
class rifle1
{
name = "rifle1";
sound[] = {"\music\rifle1.ogg", db+10, 1.0};
};
class mgun_burst1
{
name = "mgburst";
sound[] = {"\music\mgun_burst1.ogg", db+10, 1.0};
};
class mgun_burst2
{
name = "mgburst2";
sound[] = {"\music\mgun_burst2.ogg", db+10, 1.0};
};
class mgun_burst3
{
name = "mgburst3";
sound[] = {"\music\mgun_burst3.ogg", db+10, 1.0};
};
class mgun_burst4
{
name = "mgburst4";
sound[] = {"\music\mgun_burst4.ogg", db+10, 1.0};
};
};
...if I'm not mistaken. Good luck!