The prompt and DeviantArt link for the 19th.
There are two slings that are of use by the USSC forces. One secures an injured limb to prevent further injury; the other secures the battle rifle so that it doesn’t get misplaced. The first one usually gets used in the event of someone doing something stupid. The second is used to prevent someone from doing something stupid. The first tends to be far more successful than the second, as can be attested to by the typical pay records of most USSC units.