I remember hand grenade day in Army basic training, and at the time what struck me was that the grenades going off looked and sounded like what artillery does in the movies. Spine-jarring explosions, 25-foot-tall clouds of dirt and smoke, etc. Later on (at air defense school, for some reason) we did a claymore mine at one of our live fire events, and it was far, far louder and vicious than the POP and shower of sparks that Hollywood would have given us. I can't even imagine what it would be like to be near a real artillery round landing.
It is really a very big blast, like an artillery blast like you say. I was given three opportunities to throw hand grenades during my conscription training.
First one was in a purpose-built field, where we were hunkered down in a concrete hole and threw the frag-grenade onto gravel.
The second was when were having an exercise of storming a machinegun-nest on top of a small ridge in the forest. So first we move by leapfrog (a combat pair) firing, then climbed a small ridge and threw over a live frag-grenade on to the "machinegun-nest".
Third time was when we were doing a urban combat exercise. In the middle of the forest they had a roofless building with several rooms, again purpose-built for training with live grenades, with dust floors. We were given two grenades each, one which was a chock grenade ( not flash , again doing the exercise as a combat pair. Really big blasts.
