Federal's Hydra-Shok ammunition was first released in 1989 in response to a request from the FBI for hollow-point ammunition that offered superior terminal ballistics.

In the years that followed, it has been received as one of the best defensive lines of jacketed hollow point ammo in the shooting sports industry.

So has its cousin, Federal HST, which was released in 2002, and also designed for the FBI and law enforcement.

If you're familiar with either, you might know that HST stands for “Hydra-Shok Technology,” so the two lines (on top of the fact that they are produced by the same manufacturer) are very similar.

But how are they different? Let's take a closer look.

No More Center Post, but You Still Get Optimal Penetration, and Still No Plugging

Hollow-point ammunition is designed to expand (upset, in ballistic terminology) upon impact with a target, specifically a soft target.

However, a common issue with hollow-point ammunition is a phenomenon known as plugging, during which the hollow center of the bullet's nose is “plugged” with material as it passes through an obstacle before reaches its intended target.

Plugging can have disastrous consequences; not only does it interfere with expansion and energy transfer which are necessary to neutralize a hostile target, but a plugged hollow point may also over-penetrate, endangering other targets behind the intended one.

Federal's Hydra-Shok was made with a center post in the hollow of the nose which was intended to produce optimal penetration characteristics.

When Federal HST was released in 2002, shooters were quick to note that the center post was gone, but testing still showed that it offered similar penetration to the original line, and did not plug, even when passing through multiple barriers of fabric.

A Deeply Skived Jacket for Predictable Upset (Consistent Expansion)

Both Federal Hydra-Shok and HST ammo are designed for predicable upset, but if you look at fired rounds that have been recovered, they look remarkably different.

Fired Hydra-Shok bullets look more like a classic mushroom with a flattened nose. In some cases, the jacket hardly tears at all and the bullet expands away evenly through deformation around the nose.

This is not the case with Federal HST ammo. Recovered, fired HST projectiles look like a 6-pointed star.

This is a product of another difference between the two classes of bullets. Federal HST bullets are made with deeply skived jackets.

A skive is like a “score” in the jacket of the bullet that serves as a weak area. When the bullet strikes a soft target, the jacket tears away, allowing the bullet to upset and transfer its energy.

This design, which produced a star-like shape rather than a generally expanded circumference, not only produces extremely predictable expansion but also helps optimize penetration.

In a nutshell, what Federal HST ammo delivers is optimal penetration and upset, with a minimized risk of plugging and overpenetration.

Can You Get Federal HST Online?

You can get both Federal HST and Hydra-Shok online at Bucking Horse Outpost, at competitive prices. Check out their Federal Ammunition collection via the previous link.