They sound nothing like bullet impacts on anything.
It sounds tinny due to the audio being equalized for a speech in a large open noisy area.
The report that you hear afterward is the echo, the report, of the gunshot, as the sound is in a fairly large open area and it bounces/echoes through the environment.
This confirms that it is real gunshots, not bb guns as some people who have evidently never listened to footage of gunshots are claiming.