with example you gave
list.Add(1075265, "{0}\t{1}", 0, this.Capacity); // Ammo: ~1_QUANTITY~/~2_CAPACITY~ arrows
if it is properties list you can change it like so
list.Add("Ammo: {0}\t{1}", 0, this.Capacity); // Ammo: ~1_QUANTITY~/~2_CAPACITY~ arrows
remove the number and comma following and add your custom word inside the quote marks