>>2939842>they are.depends on the law, to be more precise.
and no, not always they have TNT. many stun grenades around the world have the equivalent of just 4gr of TNT.
but apparently the french ones do have TNT and your 25gr is not only correct, it completely re-designs my recommendation of using safety gloves to pick up stun grenades.
checking the calculations, it's a 104,600 joules of energy release for 25gr. commercial gloves at best handle 5 to 10 joules, under EN 388:2016 and ANSI/ISEA 138-2019 standards. Both are tests using a 2.5k weight dropped at 20.4 cm absorbing 6 to 7kN. With that 104,600 joules of energy, to simulate the same impact, one would have to drope the same 2.5kg weight at 16.1m. A bit less, because explosions move the energy to all directions.
the only coping mechanism is to use eargear.