It's easy in the second case 1 rocket= 25 bullets But in the first case, what are they going to do? round it up like you said? Also now that I think of it, I should have asked about ammo conversion, not just heavy, but that's what I was more curious about.

In mind when a player kills another player and some heavy ammo spills out onto the ground, they shouldn't be thinking about "I wonder if I can recursively figure out how much ammo my opponent had when he died?", they should be going "OH SWEET NOW I CAN DISH OUT SOME DEATH!" Especially as players aren't privy to the amount of ammo that their opponents are carrying before they die, it seems more important to design the system in a way feels about fair to the guy picking it up, as long as he doesn't feel jipped off by the ammo conversion process, then he should be so immersed in the gameplay that he doesn't think about the math going on behind the scenes. I imagine that ultimately their system is going to rely on rounding to tiers like I mentioned, or perhaps they could just carry the excess over for the next time you pick up heavy ammo. By this I mean, let's say that instead of focusing on discrete ammo as units of measurement, heavy ammo is measured using heavy points. Let's say that a heavy point is equal to a heavy machine gun bullet, and twenty five heavy points are equal to a rocket, and that picking up a heavy ammo crate gives you 100 heavy ammo points. So, a guardian with an empty heavy machine gun comes along, picks up a crate, gets 100 heavy ammo points which translate to 100 heavy machine gun bullets. He fires 67 rounds and then dies to another guardian who uses a rocket launcher. This guardian picks up the remaining 33 bullets, which translates to one rocket and a remainder of 8 heavy bullets. This guardian dies to another rocket launcher using guardian who had an empty rocket launcher and 17 heavy points... that guardian picks up the other guardian's 33 heavy points which brings him up to 50 heavy points, two rockets! With a pure rounding system he would only have gotten one rocket, but because of this remainder system, he gets two. This approach is not perfect mind you. If I have rockets and I kill a guy with 8 heavy points, should the game display him dropping heavy ammo? If it does, then I'm going to rush over only to find that I don't actually gain a rocket, and I'm going to be upset. If it doesn't, then I might miss out on scrap heavy points that might eventually add up to a rocket. Maybe it's okay if the game actively tracks how many heavy points a player has, so they can see the small increment that builds up to a rocket? Or would that be too much information for players? That's why a combination of both a rounding system and a remainder system seems like the best solution at the moment. Oh yeah, further complications, remember that you can swap out your loadout in the middle of a game, so my earlier comment about "Yeah players don't see how much ammo their opponents have" doesn't quite apply in that instance... It might be easiest to take the draconian route and say "You're swapping out your loadout in the middle of combat? YOU LOSE YOUR AMMO!" This is why Game Design is fun, there's no clear answer, there's numerous variables, it's just pure problem solving and balancing different approaches against each other and weighting the merits and drawbacks. Needless to say I'm very curious to see how Bungie approaches this :)