Speed of Fragmentation

[Nolo]

I'm looking at different loads and speeds for concept ammunition, and I was wondering what the speed of reliable fragmentation (as opposed to expansion) for a hollowpoint/softpoint is. I know that 5.56/.223 fragments well, along with other fast (2700+ fps) cartridges, but I wanted to know what the lower limit is. For instance, do 7.62x39 and .30-30 fragment similarly? I know that most pistol cartridges expand (not fragment), like 9mm and .45ACP, but do higher speed pistol cartridges (like .357 Magnum, .44 Magnum, 5.7 FN, 4.6 HK, and .357 Sig) fragment or expand? And, if they do fragment, do they do it reliably? Also, does the weight of the projectile influence fragmentation?
Thanks ahead of time.
P.S.
The round I'm currently most interested in pushes a 270-grain .40 caliber bullet at 2300 f/s.

 

[alucard0822]

Idealy a soft point or a "functional" hollow point will not fragment, and actually retain as much of it's mass as possible.
the three basic wounding mechanisms are fragmentation, expansion, and retension (tumbling or penetration)

ball ammo is designed mostly for retension, which preserves the best penetration, in the case of 5.56 the bullet is not strong enough to withstand yaw through flesh with an impact speed of about 2700+fps, and it will fragment. most game bullets are designed to expand as much as they can while maximizing penetration.
there are hollow point rifle bullets that are designed to fragment, or in the case of match bullets, they are designed for accuracy and not terminal ballistics, but the hollow point is more of a manufacturing necessity than to initiate expansion. and is not a "functional" hollow point

 

[Nolo]

Oh. Ha! I thought the .223 HPs were designed to fragment...

 

[alucard0822]

added a note to my previous post to clarify fragmenting hollow points (or ballistic tip) like hornandy v-max and sierra varmint bullets where the hollow point is either capped with a polymer tip or left alone, either way it is basically a way to get the lead in the jacket with a solid base, and then form the tip of the jacket. instead of FMJ where the base is exposed lead or TMJ that uses a deposition process to seal the lead. hence the difference between a "functional" HP like gold dots, or hydra shocks, and a "non-functional" HP like SMK or varminters

 

[LAK]

Bullet design, materials, construction. Besides the more complicated designs, such as the types for hunting with steel inserts like the Winchester Failsafe etc, basic jacketed lead core bullets will reach a velocity threshold where they will literally go to pieces on soft tissue. Most manufacturers have regulated this threshold using jacket thickness as the governing factor. Just about any bullet will go to pieces impacting if driven fast enough.

 

[Kentak]

It is my understanding from years of reading about guns and ammo, that handgun bullets are not designed to, and probably won't, fragment reliably at normal handgun velocities. The exception would be hitting bone, and, of course, frangible bullets.

K

 

[MinnMooney]

Caliber has little to do with fragmentation.
Speed helps in fragmentation but what really does it is the design of the bullet.
Little, thin-skinned critters like prairie dogs would have a fmj pass right thru and just make a pencil hole (at any velocity) but the plastic-tipped varmint bullets (V-Max by Hornady, as but one example) & hollow points explode on impact at a wide range of velocities. This characteristic helps, also, in not having ricochets flying off into a far-off ranch house or cow.
Bullets for heavy, thick-skinned animals and dangerous beasties have non-fraging shells with some being solids. They won't fragment so that they'll make it thru the tough hide and get to the vitals inside.