The "10" in "10x" refers to shots per second. This cannon was so powerful that it blew itself up. The destruction it caused was considerably large, though.
Since a pulser's maximum speed is five times per second, I needed to make two with the other one turning on a few seconds later. I basically mashed two cannons into one.
This was not intended, but the cannon shot in two directions. Most of the TNT went forward, so that was good.
The TNT was widespread vertically (it flew at many different altitudes). The cannon misfired, which is very common with high speeds, and blew itself up.
Although the cannon explodes, it causes much destruction. The ground will have many craters.
I would not recommend trying to build the cannon this way, as it will break itself. However, this still could work with some modifications.