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M193 ammunition: Everything you wanted to know

M193 ammunition: Everything you wanted to know

M193 ammunition is a type of brass-cased, lead-core rifle ammunition developed by the US military and chambered in 5.56x45mm NATO. It is a 55 grain lead bullet with a full metal jacket (made of copper). The M193 has been standard issue rifle ammunition for the U.S. Military since the 1960’s.

However, it is seeing less use since the introduction of M855 and other newer loads as well.

What is M193?

It is a high velocity, small caliber round that was designed for use in the M16 rifle. The M16/M4 is the standard issue rifle for the United States military.

M193 was developed as the standard ammunition in 5.56x45mm for the US military in the 1960’s. The M193 round is also used in a variety of other rifles, including most AR-15s. M193 is a ‘ball’ round, a common term for rounds with a full metal jacket (FMJ) bullet.

Ideal twist rate for the M193

The original M16 had a 1/14 twist barrel. However, it was discovered that in extremely cold conditions, this was not sufficient for stabilizing the 55 grain projectile. So, the M16A1 had a 1/12 twist barrel to remedy this issue.

While the 1/12 twist rate is ideal for the 55 grain M193 bullet, it is generally accurate enough in 1/9 and even 1/7 twist barrels. At least for combat use, it is a pretty flexible round for the most part.

How accurate is M193 ammunition?

M193 is generally considered to be accurate enough for combat use out to around 500 yards. M193 has a relatively flat trajectory and can be used effectively at long range with the proper zero. However, wind can play a major factor at that range for this particular round.

M193 is not designed for long range precision shooting. For that, you will want to look into heavier rounds like the 77 grain MK262 Mod 0.

Primary wounding mechanism for M193 – Fragmentation

The primary wounding mechanism of M193 ammo is that it fragments under certain conditions.

When M193 hits soft tissue, it begins to yaw or tumble. The force from this tumbling, when the bullet is traveling fast enough, can often result in the bullet tearing itself apart at the cannelure, which is the weakest part of the bullet.

Fragmentation is generally more violent and reliable at higher velocities. 2700 feet per second is often considered the “Fragmentation threshold” for M193, though fragmentation can occur at speeds as low as 2500 feet per second.

M193 ammunition: Everything you wanted to know

Fragmentation is not a perfect science in the real world. Lab results aren’t always going to be the same as street results. There are multiple factors that determine if fragmentation will occur in an M193 projectile. They include:

  • Variability of bullet construction, jacket thickness, and cannelure
  • Velocity upon impact
  • Depth of penetration in soft tissue

If an M193 bullet hits a limb or even the chest/belly of a malnourished or extremely thin individual, that could limit the ability of the bullet to fragment. Fragmentation doesn’t usually begin until it has traveled in soft tissue for over 10 inches.

M193 ammunition: Everything you wanted to know

M193 fragmentation threshold distances by barrel length

Velocity with the M193 is determined by barrel length as well as other environmental conditions. It is important to understand that the M193 was created to work best with a 20″ barrel like the M16 has. Since shorter barrels have become more common, you should know the limitations it places on effective fragmentation range.

This is based on the 2700 feet per second threshold for the M193.

20″ barrel – 200 yards

16″ barrel – 150 yards

14.5″ barrel – 100 yards

11.5″ barrel – 40 yards

What is M193’s muzzle velocity?

The following velocities are rough estimates for M193 rounded to about the nearest hundredth.

20″ barrel – 3200 feet per second

16″ barrel – 3100 feet per second

14.5″ barrel – 3000 feet per second

11.5″ barrel – 2800 feet per second

What is the best application for M193 spec ammo?

It’s actually pretty good for self defense as it is affordable, easy to find, and generally pretty effective at ranges under 50-100 yards.

M193 is also great for practice/training and general SHTF stockpile ammo.

It’s not the most accurate ammo there is, but it is accurate enough for most combat and training applications.

Is M193 spec ammo good round for hunting deer?

No. The fragmentation factor would destroy too much of the meat at closer ranges. At further ranges, it would probably do too little damage. You’d be better off finding a good quality hunting round in .223, such as Trophy Bonded Bear Claw.

Is XM193 ammunition the same thing as M193?

XM193 is a commercial version of M193 ammunition. It is manufactured to the same specifications as M193, but may not be held to the same quality control standards as M193.

However, if it is manufactured by an ammunition plant contracted with the US military, it might be nearly identical in most instances. If it is made by another manufacturer, all bets are off. You may need to test it for velocity and ability to fragment.

Federal or Winchester XM193 (also known as Q3131A) is a good bet for getting M193 spec ammo. They are commonly used by police and civilians.

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