Per Request, this is the back clip for the Cassian Blaster Pistol.

I consider this to be "in the style of" the movie prop and not 100% accurate.
In short the movie prop is made from an airsoft rifle.

I found airsoft rifles that had the removable stock with the correct clip on the back like in the movie, but the right hand side detail was all wrong.

I also found airsoft rifles with the correct right hand side detail, but not the removable, clip on stock.

I never found the exact airsoft rifle the movie prop people used. (I'm guessing it is only available in Europe or something like that. Or costs $300 as i was not looking to cut up expensive airsoft rifles.)

It was easiest for me to print the back part for the clip on stock for the correct, right hand side detail.
This is for looks only and is just glued on. It is not meant to support a stock, or to clip in with any existing stock.