A firearm mounting assembly includes a clamp that is attachable to a support panel. A screw threadably engages the clamp and the screw is rotatable in a tightening direction for securing the clamp to the support panel. Conversely, the screw is rotatable in a loosening direction for releasing the clamp from the support panel. A mount is rotatably disposed on the first bracket and the mount has a channel that is integrated into the mount. A block is pivotally positioned in the channel in the mount and the block is structured to conform to a magazine receiver of an AR-15 firearm. In this way the block facilitates the AR-15 to be mounted to the support panel for servicing the AR-15.