Is there something wrong with this radar gun?

i have a stalker sport 2 gun i bought used. im throwing fastballs that look like theyre at least 80mph but the gun gives a reading of 56mph to 60mph. im find it hard to believe its accurate, but i could be wrong. we tried every setting on it. a couple of times it said 78mph.
the catcher says im hitting the glove really hard and not to worry about the gun reading. just doesnt seem right.
i was just wondering does anyone have experience with this gun, do they need to be calibrated or something?

Do you have a tuning fork? If not buy one, can find on eBay. Should tell you if the guns accurate.

The tuning fork has to match the the band the gun operates on.

Get someone to ride by in a car…you’ll get a good idea of the gun’s accuracy.

Yeah, it’s a k band, not hard to find & inexpensive. Can pull up the sport 2 on stalker site and find with the accessories for $23. Handy to have if you own a radar gun.

I had a gun that was part of my equipment that was in bus accident. We got T-boned by a driver who ran a light. In any event, I thought the thing was damaged slightly so I found one of the signs that police use that tells on-coming traffic how fast there going, then I set myself in a lawn chair next to it and compared my readings with that of the illuminated MPH that flashed on the display. In the final analysis I found my pointer was about a mile per hour or so off from the street display.
However, I want to suggest being careful while using this method. You don’t want to distract drivers by giving them the impression that you’re recording the speed at which they’re driving. So, use your friend’s car, your family car, or someone that you know.