Gamo Gamo Urban bolt opens after every shot

Bolt jump on the BSA MMC based guns is common. BSA guns that use the MMC originally designed for the Multi Movement Cocking set up which did not have a traditional bolt.(Hornet, Lonestar, Huntsman, Gamo Dynamax ect)

The bolt versions of the MMC based guns all do it on high power. There are a few tricks to fix it but outside of a heavier handle there are no easy fixes that I'm aware of.