It is possible, and I will show you what to do:
[cpp]bool CCharacter::GiveWeapon(int Weapon, int Ammo)
{
if(m_aWeapons[Weapon].m_Ammo < g_pData->m_Weapons.m_aId[Weapon].m_Maxammo || !m_aWeapons[Weapon].m_Got)
{
m_aWeapons[Weapon].m_Got = true;
m_aWeapons[Weapon].m_Ammo = min(g_pData->m_Weapons.m_aId[Weapon].m_Maxammo, Ammo);
return true;
}
return false;
}[/cpp]

This function is used when you get a weapon, it gives you "Ammo" new projectiles and to get more, you need to change g_pData->m_Weapons.m_aid[Weapon].m_Maxammo for all weapons you want to change it or you need special cases in this function:
[cpp]if(Weapon == WEAPON_GRENADE) {
if(m_aWeapons[Weapon].m_Ammo < 20 || !m_aWeapons[Weapon].m_Got)//20 Maxammo
{
m_aWeapons[Weapon].m_Got = true;
m_aWeapons[Weapon].m_Ammo = min(20, Ammo);
return true;
}
return false;
}[/cpp]
I really hope you understand how the min function works

Take a look at FireWeapon() at CCharacter. Projectiles get created there, just check the parameters of the CProjectile Constructor, amd modify them in CCharacter's FireWeapon (the switch case)