on the PS3, i found whatever ammo you hot-key to the weapon you want to use, you must have that weapon for the ammo you want to hot-key for a different weapon, and whatever ammo you hot-key is depleted, you do not have to keep the weapon once the ammo has been hot-keyed, i keep it in a box.
for example, im using the 3K microfusion cells that i have as ammo for the sniper rifle, there is no difference in damage and rate of fire, just that i have more ammo to use, i used a wepon that takes MF cells to get the ammo hot-keyed and put the weapon away in a box afterwards.
i was not able to get the MF Hyperbreeder to fire anything other than its own ammo, regardless of what i did, i could see the ammo was changing but the actual ammo it fired did not.
one great thing about this glitch is the C4.
i have the MF cells hot-keyed, simply equip C4, switch to the hot-key that has the MF cells, drop some C4, disarm and pick it up, rinse/repeat until you have enough you desire to sell or use.
just be careful not to drop too many close together, they tend to all blow up as it happened to me by dropping about 20 of them in a pile.
with this type C4 trick, you can essentially buy everything from the merchants and get your money back.
if you choose to do that, be aware the merchants have a limit on the amount of caps they can hold, i bought 40K worth of items from GRA and tried to sell the C4 trick back to the GRA vendor to get the caps back, the vendor was taking the C4 but i was not getting any caps at all.
i had to wait in-game one hour to reset the GRA vendor back to 8K caps, no biggie, ill reclaim the caps from the many other vendors all around anyhow, it wont take much time at all.
i think ill have Raul carry as much C4 as possible now, just for selling, LOL
also as a note, i do not lose the ability to hot-key different ammo to any weapon while teleporting, not on the PS3