This is a simple, friction fit, barrel lock for both the Classic Army and Ares Stoner 96 LMG AEGs. Maybe you're one of those that accidentally released your barrel in the middle of a game? Here ya go. Again, just a friction fit and it should hold very well from my experience. Even if you loose one, it's like 2 cents worth of filament to print. I used PETG 2 walls 10% infill.
The author marked this model as their own original creation.