Is FMJ Ammo Good For Self Defense?

A few days ago while standing at the sporting goods counter at my local discount store, a customer holding a box of 9mm FMJ ask the young employee if these were good enough for home protection. The kid shrugged and said they all punch holes. So this got me thinking this may be a good subject to for the blog. What to look for in a self defense bullet.

Is FMJ (full metal jacket) ammo good for self defense? While it’s true “they all punch holes” there are better choices. All of the major ammunition companies make specialty self defense ammo. It will generally be based on a hollow point bullet.

In the Beginning All Bullets Were Just Lead.

Not to delve to deep into history but all bullets used to be solid lead. You can still buy some calibers with a round nose lead bullet. The problem with the lead bullet is that when it’s fired it engages the rifling in the barrel, being a very soft metal the rifling scraps off small amounts of lead inside of the barrel. After firing many rounds this built up lead in the barrel will affect the accuracy of the shot.

Enter the Metal Jacket

To solve this problem the the full metal jacket was developed. The center of these bullets is still lead but is covered in a copper jacket.

The outer copper jacket is hard enough that it does not leave lead in the rifling thus improving the accuracy. Unlike the soft lead bullet the full metal jacket does not deform upon impact with soft targets. it is not uncommon for these projectiles to cause a thru and thru wound meaning in one side and out the other.

Now at first blush this sounds like it would be pretty effective for self defense. However a bullet that passes through a body has not expended all of its energy. These bullets may have enough energy to continue though a wall and injure someone in an adjoining room or even outside of the building.

The bullet would also be more effective for self defense if it could expend more of its energy on impact.

The Soft Nosed Bullet.

The soft nosed bullet is a partially jacketed bullet . The copper jacket covers all of the bullet with the exception of the nose. This exposes the soft lead core.

On impact this exposed lead nose begins to deform causing the projectile to mushroom. This expanded bullet drags more on the tissue and expends more of its energy. These bullets can sometimes still make it through the target but at slower speed than the FMJ.

The Hollow Point.

Most Self Defense ammo will be of the hollow point type. The hollow point is a fully jacketed bullet but with a hole in the nose that extends down into the bullet.

When this bullet strikes it’s target it acts almost like a cookie cutter at first, but as the base of the bullet enters the target the the force of the tissue inside the hole forces the walls of the bullet to fan out and expand. This wound channel will be larger than the original caliber of the bullet.

If this works as designed this bullet will likely expend its energy fully if it hits a heavy part of the body like the torso.

Note I said if. The hollow point can at times have an issue. Mainly when it passes through heavy clothing the cookie cutter hole may fill with soft cloth. This can cause the expansion to fail at least in part.

Polymer Tip Bullets

To combat the cloth packing problem most ammo manufactures have introduced polymer tip bullets.

These bullets are essentially a hollow point with a conical hole meaning the hole is wider at the nose and narrow at the base. The hole is filled with a polymer plug.

This does a couple of things first it restores the aerodynamics of a solid nosed bullet. Secondly the polymer plug acts like a wedge on contact irregardless of clothing the plug is forced back into the bullet and causes the expansion. This also insures that the energy is expended.

So to Answer The Question.

Yes Full Metal Jacket bullets will punch holes but there are far better choices for self defense ammo. Both from a functional point and from the safety stand point. The hollow point and the polymer tip will help to mitigate the danger of the round passing through the intended target and striking an unintended bystander. Of coarse you are responsible for knowing whats behind your target.

The Concealed Carry Guy