Whenever I use grenades in multiplayer I tend to run out very quickly when I am actively using them or forget about them if I try to keep them for bad situations. In singleplayer grenades are easily found, but in multiplayer I often times find that they are hard to come by, especially if other teammates are using them as well.
The same system applies to thermal clips, although they get restocked faster with more clips.
I have previously said that there is a limit on how many grenades you can pick up in a certain time period, that isn’t the case. I assumed that the thermal clip supply was the same as the grenade supply, but they are actually two different systems. The thermal clip supply is stocked up more frequently and there are more clips available. On bronze they are restocked in around 10 seconds. The grenade supply seems to take around half a minute, maybe a little more or less. On bronze you get a maximum of 2 grenades back when the supply box is fully stocked, sometimes your teammates may take one or all of the grenades because both the thermal clip and grenade supplies are shared.
On silver the system is very similar, except you get one less grenade per supply crate and the grenades seem to take longer to restock. I haven’t noticed that about the thermal clips though. I haven’t experimented with the gold challenge a lot, but I assume that grenades are even more sparse than on silver.
Maximizing the Amount of Grenades Available
Each supply box restocks separately, so if you go to two on silver you get 2 grenades back. The time it takes for them to be restocked is also independent of each other.
For the round in which you don’t have to stay in an area for the objective be sure to keep moving around the map so that you are always headed to the next resupply crate. Especially on bronze I have finished entire missions with always at least 1 grenade in my pocket.
When you do have to stay in one area for an objective think about where the next ammo crate is. Keep an eye on the route there and keep it clear so that you can easily get there and back quickly. Be sure to use your first set of grenades early and use resupply because the earlier you resupply the earlier the crate is restocked. Don’t waste the grenades on basic enemies though, find out where the boss enemies are and damage them as much as possible.
Your resupply packs stock your ammo and grenades full, regardless of how much is available to you. So if you have one grenade slot you only get one grenade, but if you have 3 you also get three grenades back. The same goes for the thermal clips.
At the end of each round you get some ammunition back. I am not entirely certain about how the system works, but generally I seem to get half my thermal clips refilled. You don’t get any grenades back. The resupply occurs as soon as the last enemy is dead. If you were shooting that enemy it is likely that you will be a few shots short because you probably kept firing for a little while after the enemy was actually dead. I do that a lot too and it is good practice to ensure that your enemy is really dead.