So in this world I'm building there's a bunch of reasons to, at some point, stop being nice and make sure someone is really, really dead. For this purpose they decided to weaponize black holes. Nothing says "stay down" as ripping them to shreds, heating them up as they accelerate, crushing them into a tiny sphere of fused matter around a singularity in space-time and then even that matter they consisted of is erased from the universe due to Hawking radiation.
First to get this out of the way, black holes evaporate, and as this thread says: Black hole launcher.
A one second black hole would already be thousands of tons. This handheld miniature black hole weapon wouldn't have anywhere near that mass so its ammo would evaporate almost instantly upon firing, where "evaporate" will be closer to "explode violently". To combat this the weapon would either need to use some kind of anti-quantum beam in the black hole's path to reduce the amount of Hawking radiation until it reaches the target, or the black hole would need to be fired really really fast. That last one doesn't seem very useful as it would still be evaporating violently while traveling to the target, unleashing most of its energy at the launch-point. So maybe there's a better idea out there?
How the (handheld) weapon works (as far as my knowledge on these subjects go):
Our Sun does not have the temperature and pressure to actually perform fusion in its core. As particles move they are subject to quantum effects, one of which means they have a chance to be somewhere else entirely. This allows these particles to "tunnel" into another particle they wouldn't be able to fuse with normally and start a fusion reaction. The temperature and pressure of the sun only make the chance of this happening more likely. The weapon has a carefully calibrated system that changes the chances and makes it almost 100% likely that a large amount of particles with a certain mass will converge simultaneously and form a black-hole, preferably with a tiny delay so that this happens a distance after the projectile has left the barrel.
So for my question: How effective would such a weapon be? Would it basically be close to an anti-matter bomb in that it just releases butt-loads of energy in a short period of time (to which there's protection in this universe, against such energy releases not antimatter which they sometimes use as an alternative to black-hole launchers), or would it really be able to be shot at a hostile say 100 m away and absorb something the size and weight of a cow without adding more techno-magic than the quantum-chance alteration at the end of the barrel of this weapon? Preferably without turning the owner of the weapon into part of the black hole.