I reviewed a SU-16 a long time ago here. The review does not seem to be findable in the search function. (over 3 years ago).

Basically I found the gun to be wildly inaccurate. Depending on how I held the fore stock, the point of impact would change. I put a laser sighting device in the barrel and played with it one night. As I gripped the rifle I could see the point of aim remained fixed, but the point of impact moved. The barrel is just too thin and mounted to the fore stock in a manner that transmits force to the barrel causing it to bend slightly.

I sold mine.

Nomad