In the world of ammunition, the terms SS109 and M855 often come up, especially when discussing 5.56x45mm NATO rounds. While these two types of ammunition are similar in many ways, there are some key differences that set them apart. In this article, we’ll explore the history, design, and performance of SS109 and M855 ammo, and help you understand the distinctions between these two popular types of ammunition.
SS109
The SS109 was developed in the 1970s by FN Herstal, a Belgian firearms manufacturer. It was designed as a replacement for the M193 round, which was the standard issue for the U.S. military at the time. The SS109 was adopted by NATO in 1980 as the standard 5.56x45mm round.
M855
The M855, on the other hand, is a U.S. military designation for the SS109 round. The M855 was adopted by the U.S. Army in the early 1980s as a replacement for the M193 round. The M855 is essentially the same as the SS109, but with a few minor differences.
Design and Construction
Both SS109 and M855 rounds are 5.56x45mm NATO rounds, meaning they have a 5.56mm diameter bullet and a 45mm case length. They are both designed for use in rifles like the M16 and AR-15.
The SS109 and M855 rounds both have a 62-grain bullet, which is heavier than the 55-grain bullet used in the M193 round. The heavier bullet provides better long-range performance and penetration.
Key Differences Between SS109 and M855
One of the key differences between the SS109 and M855 rounds is the composition of the bullet. The SS109 bullet has a lead core with a steel penetrator tip, while the M855 bullet has a lead core with a steel penetrator tip and a copper jacket. The copper jacket on the M855 bullet helps to improve the round’s performance in certain situations, such as when shooting through barriers.
SS109 and M855 Performance
In terms of performance, both SS109 and M855 rounds are similar. They are both capable of penetrating soft body armor and light cover, thanks to their steel penetrator tips. However, the M855 round is generally considered to be more effective against hard targets, such as vehicle armor, due to its copper jacket.
SS109 and M855 Accuracy
Another difference between the two rounds is their accuracy. The SS109 round is known for its excellent accuracy at longer ranges, while the M855 round is generally considered to be less accurate at long range. This is due to the copper jacket on the M855 round, which can cause the bullet to yaw and lose accuracy at longer distances.
In the United States, SS109 and M855 rounds are both classified as “armor piercing” by the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF).