I know how I'd do it with a console-style gamepad. I'd use the digital pad up and down axis to scroll through the fire modes. It is very similar to how real-world weapons do it. As for the specialist ammo some weapons automatically come with it, like the Stalker Pattern Bolter, others either have a special ammo clip for each type or load the individual special Bolt Round as it is a rare-type of ammo.
well if EC want to stay with the pool of single bullets system then we can make the use of special ammos easy you press a button and your char loads a mag into his weapon your ammo pool now switches to the special ammo this can be repeated as often you want to but i would prefer the magazin system its more logic and realistic press R to load in the next most full magazine not fully empty magazines will be saved for later use hold R for 5-10 sec to combine not full magazines to full ones press a button to switch ammo type
Some games solve this by holding R to switch ammo and reload (Metro 2033 and the sequel), if we have more than two types of ammo we could use hotkeys for example, 1-2 weapons, 3-4 utility items, 5 regular ammo, 6 kraken ammo, 7 vengeance rounds etc.
