Here is a list of materials you will need in order to mount the sling:
Crosman R39 Airsoft Rifle
key ring with 1.125 inch radius
laptop shoulder strap with hooks
If the hooks on the strap are too wide, you will need another key ring with a .75 inch radius.
Step 1: Mount the Key Ring
Mount the bigger key ring on the two holes right above the barrel. If necessary, mount the smaller key ring onto the hole at the back of the stock.
Step 2: Clip the First Hook
Clip the first hook of the shoulder strap onto the key ring.
Step 3: Clip the Second Hook
Clip the second hook onto the hole near the back of the stock or the second key ring if you had to mount another key ring.
Step 4: You're Done! Wasn't that easy?
Congratulations! You have now successfully mounted a sling onto your Crosman R39 with no internal modifications! Be sure to follow me for more airsoft tips, sling tutorials, and guides!