It may seem quite a lot crazy, but I tried my best to make it hard to abuse.
So, essentially, you know - there are those heavy machine guns that you need to deploy before shooting. (not in-game)
BUT, there are also automatic grenade launchers, which work more or less the same way (having to be deployed).
So why not introduce something like that into Ace of Spades?
You might be thinking it's OP, its griefer's toy, it's unrealistic.
Let me tell you:
"it's overpowered"
If you consider the fact you have to deploy it (which takes some time), and moving it makes you slower and unable to attack, then it's probably not very OP.
"it's abusable by griefers"
Maybe it would. BUT, what if those grenades shot from this AGL wouldn't harm the terrain? After all, they are smaller than hand grenades.
"it's unrealistic"
First AGLs were used in Vietnam War, in which the game supposedly takes place.
To pick the AGL up, you could click a new key type, called "Action" (default: Tab), which would also allow you to use the tent to resupply if wanted to (it would no longer refill it automatically, but it would still do it instantly). Picking the AGL up would be instant, but putting it down would take roughly 2 seconds.
The nades would be somewhat weaker than those you could throw, but they would travel longer distance, comapred to throwable hand grenades.
Those AGLs would spawn in random places around the map, with roughly 20 grenades in the mag. If you want to refill this weapon:
When you go to tent (or when you spawn), you can choose between three hand grenades, or a 20-round box of grenades that you can use to refill the AGL. Note that those grenades aren't throwable (what did you expect?).
You CAN also walk with this all the way to the tent, but it doesn't seem to make much sense, does it?
When carrying AGL, you walk roughly as fast when crouching and you can't sprint. You can only jump one block high as well, which would make roads once more reasonable (or at least sort of).
You may say that we don't need heavy weapons until vehicles are in, but tell me - are you really going to use grenade launchers against helicopters/choppers?