Editing Hollow-point bullet (section)

== History ==
Solid lead bullets, when cast from a soft alloy, will often deform and provide some expansion if they hit the target at a high velocity. This, combined with the limited velocity and penetration attainable with muzzleloading firearms, meant there was little need for extra expansion.<ref name=":0">{{Cite web |last=Jones |first=Allan |date=2016-07-15 |title=Hollowpoints: Myths & Facts |url=https://www.shootingtimes.com/editorial/hollowpoints-myths-facts/99505 |access-date=2023-09-27 |website=[[Shooting Times]] |language=en}}</ref>

The first hollow-point bullets were marketed in the late 19th century as ''express bullets'' and were hollowed out to reduce the bullet's mass and provide higher velocities. In addition to providing increased velocities, the hollow also turned out to provide significant expansion, especially when the bullets were cast in a soft [[lead]] [[alloy]]. Originally intended for rifles, the popular [[.32-20]], [[.38-40]], and [[.44-40]] calibers could also be fired in [[revolver]]s.<ref name=":0" />

With the advent of [[smokeless powder]], velocities increased, and bullets got smaller, faster, and lighter. These new bullets (especially in rifles) needed to be jacketed to handle the conditions of firing. The new [[full metal jacket bullet|full metal jacket]] bullets tended to penetrate straight through a target causing less internal damage than a bullet that expands and stops in its target. This led to the development of the [[soft-point bullet]] and later jacketed hollow-point bullets at the [[British Empire|British]] [[arsenal]] in [[Dum Dum]], near [[Kolkata|Calcutta]] around 1890. Designs included the [[.303 British|.303" Mk III, IV & V]] and the [[.455 Webley|.455" Mk III "Manstopper"]] cartridges. Although such bullet designs were quickly outlawed for use in warfare (in 1898, the [[Germany|Germans]] complained they breached the [[Laws of War]]), they steadily gained ground among hunters due to the ability to control the expansion of the new high velocity cartridges. In modern ammunition, the use of hollow points is primarily limited to handgun ammunition, which tends to operate at much lower velocities than rifle ammunition (on the order of {{convert|1000|ft/s|-2}} versus over 2,000 feet per second). At rifle velocities, a hollow point is not needed for reliable expansion and most rifle ammunition makes use of tapered jacket designs to achieve the mushrooming effect. At the lower handgun velocities, hollow point designs are generally the only design that will reliably expand.<ref name=":0" /><ref>{{Cite web |last=Association |first=National Rifle |title=An NRA Shooting Sports Journal {{!}} Why Are Hollow-Point Rifle Bullets More Accurate? |url=https://www.ssusa.org/content/why-are-hollow-point-rifle-bullets-more-accurate/ |access-date=2023-09-27 |website=An NRA Shooting Sports Journal |language=en}}</ref>

Modern hollow-point bullet designs use many different methods to provide controlled expansion, including:

* Jackets that are thinner near the front than the rear to allow easy expansion at the beginning, then a reduced expansion rate.
* Partitions in the middle of the bullet core to stop expansion at a given point.
* Bonding the lead core to the copper jacket to prevent separation and fragmentation.
* Fluted or otherwise weakened jackets to encourage expansion or fragmentation.
* Posts in the hollow cavity to cause hydraulic expansion of the bullet in tissue. While very effective in lightly clothed targets, these bullet types tend to plug up with heavy clothing materials that results in the bullet not expanding.
* Solid copper hollow points, which are far stronger than jacketed lead, and provide controlled, uniform expansion even at high velocities.
* Plastic inserts in the hollow, which provide the same profile as a full-metal-jacketed round (such as the [[Hornady]] V-Max bullet).  The plastic insert initiates the expansion of the bullet by being forced into the hollow cavity upon impact.
* Plastic inserts in the hollow to provide the same profile for feeding in semiautomatic and automatic weapons as a full-metal-jacketed round but that separate on firing while in flight or in the barrel (such as the German Geco "Action Safety" 9&nbsp;mm round)