I have purchased INCENDIARY ROUNDS for both my Combat MG mk2 as well as Carbine mk2, When i use them, why does it happen that ONLY 1 OUT OF 15 OR 20 SHOTS RESULT IN A FIRE, and all shots are just as normal? Today i used these guns in PvP, none of the enem

I have purchased INCENDIARY ROUNDS for both my Combat MG mk2 as well as Carbine mk2, When i use them, why does it happen that ONLY 1 OUT OF 15 OR 20 SHOTS RESULT IN A FIRE, and all shots are just as normal? Today i used these guns in PvP, none of the enem