will it fit the Ataman m2r bullpup tube?
I do not believe it will.
Will this mount fit on the Gamo Viper Express .22?
Will this fit on a Sumatra 2500, and allow me to attach a bipod?
Will this fit a Gamo urban .22?
Will this Bipod fit benjamin BP2220?
This is not a bipod, it is just a bracket that fits a few select guns that allows you to mount a bipod. Sadly that benjamin model is not one of the guns it fits.