New Benjamin Bulldog velocity

I have a new Benjamin bulldog from pyramid air I have been doing some testing with it and I noticed that when I was doing my velocity testing my rifle came shooting very hot compared to other chrony test I've seen online JSB 81 grains high of 960 predator polymag high of 955 Benjamin Nosler 145 grain high of 790 so I'm wondering maybe someone else had the gun prior to me and did work to it have anyone else seen these type of numbers from a stock bulldog thank you