Inverting op amp design saturates at a fraction of power supply
Check the opamp's output current rating. I expect it's in the 20-30 mA region.

A 50 ohm load is much lower impedance than most opamps can reasonably drive.
Add about 1 kilohm in series with that 50 ohm scope input : that will give about 20:1 attenuation (at the scope) and I expect you'll get around the output voltage you were expecting.