Gun Loader Model from Borderlands 2, PreSequel, or Tales From the Borderlands.
Disclaimer: I did not model this myself, I extracted the model from the game files and modified it to be printable. Some minor errors are still present, feel free to fix them (e.g. in the 'knees').
You HAVE to print this with support for obvious reasons. Removing all the support material without damaging the model was kinda hard, it took about three hours.
For my version, I used a 15% infill and 0.16mm layer height. I slowed the print down after a while because I was worried it could become loose. The whole print took about 20 hours like that.
I'm very happy with the result for me personally it is close enough to the original.
If you have any questions, feel free to ask.