This is real easy and can be done in either solo or co-op. If done in co-op, all players will pop the achievement.
Fire up a game of Daybreak and run to the three storage chests located in the back of your base (Behind where the technician hangs out). Equip as many items as you can from one chest and then drop them all on the ground. You do this by accessing your Inventory (
). Drop your items by moving your cursor over them and pressing
. Be sure to also drop your equipped weapons (gun and melee weapon).
After dropping everything you have equipped (can't drop your backpack or base knife), proceed to clean out the next chest to rinse and repeat. There should be more than enough items there for you to net the 24 needed for your achievement. I think I counted 27-28 total starting items when I did this.
If anyone has any questions or suggestions to make this solution clearer, please leave it in the comments.