If you want 240 grenades for the resident evil 1 remake on the game cube, follow these steps.

[edit] Steps

Have a grenade launcher equipped in your upper right item slot. Make sure it has the ammo you don't like.
Have any grenade ammo in your upper left item slot.
Go to any item box.
Place your ammo in any slot.
Press left and select your ammo by pressing "a".
The bar will jump to your item screen
Highlight your Grenade launcher,But do not press "a".
Press,and continue to press "a" to fill your Grenade Launcher with 240 or more, rounds. Then it will fill your inventory with 255 Pieces of ammo each slot.

[edit] Tips

Have any grenade ammo in your Launcher,and have incendiary rounds in your left slot. This is because incendiary rounds prevent Zombies from turning into Crimson Heads.
Chris does not get the grenade launcher.