Today we are discussing personal defense ammo and how it has changed overtime, leading to a new offering: external hollow points.

Ammunition Design History

Now of course we cannot begin without a brief history lesson, which are my favorite. Before the 1880s cased ammunition for repeating rifles, revolvers, and everything else used a projectile formed of uncoated lead. When these rounds struck something they would deform in an inconsistent manner, which did make the rounds more effective. However, the soft exposed lead ended up causing feeding issues, especially as machine guns were developed. To remedy this Swiss Colonel Eduard Rubin developed the full metal jacket round in 1882. This was adopted by the majority of Europe by the end of the decade because it dramatically increased reliability, and even though they didn’t know it yet, reduced lead exposure and lead poisoning.

It is often cited that the Hague Convention of 1899 was responsible for the use of FMJ rounds, because it banned the use of ‘easily expanding bullets’ in war, but the majority of Europe had already been using them for a decade.

As time went on, FMJ became the standard for 1911s and other semi-automatics, but exposed lead rounds were still easy to find for revolvers until around the 1990s, and can still be found today for .22s.

Development of Hollow Point Bullets

Hollow point rounds were born around the same time as FMJ, and were marketed as ‘express bullets.’ They became popular among hunters because the reduced weight led to greater velocity, and the hollow aspect of the round led to more controlled expansion.

They continued to be popular among shooters, and overtime advances in technology led to the very effective rounds we use today that don’t have the same vulnerabilities as their predecessors.

Hollow points expand upon impact, delivering more energy into the target and preventing overpenetration. For these reasons most if not all law enforcement agencies in the U.S. today use hollow points.

Hollow point bullet
45 ACP 230gr Federal HST before and after

External Hollow Points

These are the new kids on the block. External hollow points have not been around for more than a decade in popular circulation, however they have made a splash in the last few years. If you go on forums you will see people who swear by them and others who insist they are a gimmick.

The external hollow point’s unique design has sparked considerable debate over its effectiveness, safety, and ability. We will explore the advantages and disadvantages of external hollow points, comparing them to traditional hollow point bullets and providing a balanced assessment of their suitability for various applications.

What Are External Hollow Points?

External hollow points are bullets designed with a hollow cavity on the exterior of the projectile rather than the traditional interior hollow point. Instead of being designed to expand they retain their original shape nearly perfectly as they travel through soft-medium targets.

External hollow point
External hollow point

Because of their external channels these rounds rip, tumble, and utilize physics to create a more devastating wound cavity. The design reduces weight and increases velocity, much like the original hollow points. When traditional hollow points strike barriers and hard objects they tend to behave erratically.

External hollow points weight less than traditional hollow points, for example, a 9mm external hollow point may be 85 grains as opposed to 115-147 grains. This allows for higher velocity, and encourages behavior more similar to a rifle round.

Advantages of External Hollow Points

  • Higher velocity: These rounds often generate a 20-60% velocity increase depending on the caliber and loading.
  • Greater penetration: Due to their high velocity and lack of expansion these rounds have greater penetration
  • Barrier blind: Unlike traditional hollow points that are slowed/deformed/altered when striking a barrier, these rounds remain intact and retain greater velocity.

External hollow points are not designed to expand, rather they rip, tear, and create trauma similar to a rifle round, which results in a larger wound channel.

Disadvantages of External Hollow Points

Just like with body armor and anything else in this industry there are always tradeoffs.

  • Price and availability: These rounds cost more, in part because many are solid copper, and additionally there are fewer companies making them.
  • Feeding issues: There are potential feeding issues for semi-automatic handguns. 
  • Somewhat unproven: These rounds are new, and we don’t have decades of performance data to validate to concept like we do for traditional hollow points.
  • Over Penetration: Curious why police departments don’t issue these? Because they are high velocity rounds that are not designed to slow during expansion.

Change can be a scary thing, especially in the firearms industry, which has also contributed to a slower adaption of these rounds.

Feeding Issues

I want to touch on feeding issues when it comes to personal defense ammunition, in part because I don’t want folks to be afraid to try new innovations, but you should verify before trusting your life.

Have you ever had a gun not feed certain rounds, especially personal defense rounds? I had that problem with a particular firearm, and sold it the first chance I had. In this particular case it wasn’t just a brand or type of ammo the gun didn’t like, the firearm had fundamental flaws I wasn’t willing to pay to have corrected.

Reliability is the most important aspect of a defensive firearm. External hollow points may not feed reliably in a semi-automatic pistol. If you are interested in using these for your semi-automatic handgun I advise you to feed about 30-50 rounds through the firearm, with the magazine you plan to use. Infact, I advise this with ANY personal defense ammo you plan to stake your life on. I have seen firearms that would not feed HSTs reliably, but would feed Hornady just fine, and vice a versa.

As many 1911 fans know, sometimes the magazine can contribute to feeding problems. This is an overall rule, make sure your gun, magazine, and ammo work together flawlessly when it comes to a defensive firearm.

Try different brands of ammo, try different types of ammo, try external hollow points, just make sure whatever you choose works every time.

Final Notes

The history of ammunition is quite fascinating, and we only brushed the surface of the last century. Older rifle and revolver rounds went from simple cast lead, to full metal jacket, and hollow points too.

External hollow points represent an innovative approach to bullet design. They offer several potential advantages over traditional hollow points, particularly in terms of wound cavitation, and barrier penetration. However, they also come with some drawbacks such as increased cost, limited availability, overpenetration, and potential feeding issues.

As with any ammo, it’s important to make sure all aspects of your firearm function properly everything with that load. I am very curious to see what the future holds for these rounds, only time will ultimately tell if these rounds are a fad or for real. 

The opinions expressed in this post are those of the author and do not necessarily reflect the views and opinions of Tacticon Armament.