Make certain that the firing pin is not cocked before trying to remove the axel pin. You can lift the toggles until they first break, squeeze the trigger and let the toggles down OR you can **** it and dry fire. Then, once you've removed the upper, use the dowel to tap the pin out right to left.
If you remove the upper with the firing pin cocked, you can simply push the disconnector pin inward - not back - at the front of the sear bar to release the firing pin.
In the picture below, the disconnector pin is circled. The large numbered pin at the rear is the axel pin. It has a flange on the left side and must be removed right to left.