I propose adding weapon sling as an optional attachments that uses the same slot as the bayonet, which would slightly increase the speed of retracting the weapon at the expense of losing the ability to charge with the bayonet.
This can be purchased by one silver order for five slings.
Or simply change all attachments to unlimited usage, make bayonets, scopes and slings no longer part of the economic system.
Good idea. A gun is much more attractive when it has a sling.
If there is a problem, my guess is that you would probably have to rework the animation of the gun, and it would be hard to make different types of slings for different guns.
However, it is a feature I would like to see in the future.