Velocity does not guarantee permanent stretch cavities, therefore hyper velocity low weight for cartridge rounds don't magically create that effect. Such effects are dependent on energy, momentum's effect on the bullet and how it resists and causes resistance in tissue, expansion of the bullet both in terms of amount and speed of expansion as well as the original size of the bullet, weight is important in energy and how the energy is conserved and used as it impacts the target, a very complicated thing to try to understand. tl;dr on this part, even if a 55 grain bullet in 357 Sig is possible, it won't cause much, if any, permanent stretch or "hydrostatic shock' as it is also called, so the seemingly impressive velocity and energy aren't going to have the effect of a low power to high power rifle soft point bullet.
Second of all, momentum of heavy bullets means they tend to use their energy more efficiently in destroying tissue, lighter bullets of the same energy tend to damage less total tissue because their force in tissue tends to be wasted in worthless temporary stretch cavities. Lighter bullets will cause more temporary stretch and have less energy to keep piercing forward and stop shorter, meaning less penetration and damage. A heavier bullet will keep 'trucking" on deeper. Penetration is increased in heavy bullets by both their momentum and sectional densities, in the end in the handgun the heavier bullets for cartridge have the advantage in tissue damage out of the gate, only bullet construction can try to tip a lighter weight bullet towards better damage.
>>687477
Fragmenting bullets in handguns are a joke. Soft points and hollow points that fragment the least in rifle rounds are superior to those that fragment the most. In any case, fragmentation is undesirable, quick and wide expansion is desirable. In rifle bullets, fragmentation may be unavoidable, due to so much energy/velocity/dynamics, but even there hunting bullets that have less fragmentation are considered superior. In handguns, fragmentation is never good, 0% is always the better percentage of fragment weight and 100% is the desired retained weight of bullet. Fragments shed energy and momentum, they also shed material from the front of the expanded bullet face and decrease diameter and shape.
Fragmenting bullets do not expand well, they do not penetrate well. They offer less damage than non expanding bullets and hollow points. Liberty, RIP, et al are all gimmick trash. A 55 grain ball in 5.56 NATO will cause permanent stretch damage, not because of the fragmentation but because of the rapid and violent expansion of the bullet at high energy that leads to the bullet finally fragmenting from the violent expansion of the thin skinned bullet. A 55 grain 357 Sig bullet at 2500 fps won't even come close, won't be impressive at all.
Stick to tried and true high end hollow points of regular weight for cartridge. The whole super light weight bullet for cartridge thing was built on the junk science of the late 1970's and 1980's, but has been since heavily refuted.