Thread: JSP bullets?
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Old February 11, 2018, 10:59 AM   #23
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Originally Posted by briandg View Post
A hollow point is a bullet with a lead core an an empty space. The empty space does two things. It weakens the bullet and makes it easier to squash and spread outward, and the empty socket allows water to force it outward as well as keep it from collapsing inward.

That's a really simplistic answer.

A soft point pistol bullet works very differently. You have a lead core that is squashed and as it is smashed, it expands outward, popping open the metal jacket. The lead core is flattened and spread out, simply by impact on whatever it hits.

The hollow point is inherently weaker because the soft point is a solid plug of lead. the soft point doesn't have the empty cavity to hold that core together, it has a head start on popping open.

A soft point of similar alloy and design will not expand as easily as a hollow point at the same velocities, a soft point expands properly at the higher ranges of suggested velocities. A hollow point will expand better at the lower ranges. At low velocities the soft point will fail to expand, at high velocities, the hollow point will over expand and probably break up.

When you see a rifle bullet, they are almost all soft point, unless they have a tip insert. One of the ways that a low velocity rifle is compensated for is by loading it with a big, flat soft point bullet, and quite often, it has exposed lead to start expansion more reliably. High velocity rounds that are intended for heavy game are almost always made with small points, and fully enclosed cores, it takes a lot more energy to break them open.
Lotta general statements there, some confusing one too. While most HPs are deigned for more rapid expansion, some are made that way for ballistics. Many are the HP handgun bullets I use at the range which their manufacturer clearly states are nor designed to expand. Got some HP .45ACP plated bullets that don't expand anymore when hitting a hard rock maple bowling pin than my FMJs. There are JSPs with segmented jackets that will expand just as fast as many HPs at similar velocities. I have two types of 300 gr XTP-HPs I use in my .460s. Both look exactly the same(like the 158 grainers for .357 I showed in a previous post), but both are designed for entirely different velocities and purposes, and expand appropriately. Claiming the hole in front makes for a faster expanding bullet is not always true. The definition of a JSP is having a exposed tip made of a softer material than the jacket. A jacketed bullet(those used by civilians) is generally always a lead core surrounded by a harder alloy jacket. Exception would be steel core. HPs, unlike JSPs, may or may not have a exposed tip of softer metal(lead). FMJs can have a flat nose or pointed.......and pointed or flat makes little or no difference in expansion rates. The flat points are either for better holes in paper, protection for primers in tube feed mags, or for a larger meplat in hard cast bullets not meant to expand.

In the past, other than milsurp, rifle bullets have been mostly JSPs, because most states demand one use an expanding type bullet for hunting, and the majority of folks use factory loaded ammo. Go to any gun range nowadays and you are just as likely to see FMJ type ammo used for plinking/tarket shooting as JSPs, especially those using AR type platforms. Look at the inventory in big box stores today, and the stacks of FMJ rifle ammo generally outnumbers the stacks of JSPs.

My point is, while one may assume one type of bullet expands more at a lower velocity than another, it is not always true. It takes more than just looking at a bullet to know it's real potential for either expansion or penetration. This is where experience, manufacturer suggestions and designations shines. Hornady is good with their handgun ammo by providing a recommended velocity chart showing at which velocities their handgun bullets work best for. Other manufacturers have symbols, charts or pictures on their boxes showing what game/use their ammo is designed for.

But again to answer the OPs question, a JSP is a jacketed bullet with an exposed tip of it's softer core metal. It's use is whatever the bullet is designed for. Only thing more confusing than bullet types to new shooters is caliber designations........
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