The cocking studs on the real 50 and the 30 are the same basic diameter These training aids are much larger. Same with the dummy rounds.....closer to a 20mm than a 50 I believe but would have to mic them to be certain.
Resist the urge to cock it using your finger in the cocking handle hole. I did that once and when the accelerator snapped it opened up the tip of my index finger and bled like a stuffed pig.