The evolution of the US military rifle

Fun fact: There are currently 5 generations of military rifles.They don't really count them by generation but if you looked at when a new rifle replaced a previous generation of rifle we would be at the fifth generation with the XM7 rifle with each generation having an average lifespan of 20 years before a new model of gun is brought in to be the default rifle in the military. That doesn't mean the previous generation of gun becomes obsolete, but that both those generations of guns become part of active service. Which is why the M16 is still in service even though it was taken up by the US military in the year 1964.

First generation of US standard service rifle:

The M-1 Garand. In service during world war 2. In service from 1936 - 1959. If you have played the original Call of Duty games you would know this gun very well. It was a semi - automatic gun, meaning it could fire multiple rounds very fast unlike its predecessor, the bolt action M1903 Springfield rifle. It was the evolution of warfare to a point where you could fire multiple rounds at your enemy without reloading and was deemed a great success by the generals of the time.

Second generation of US standard service rifle:

The M-14. Entered service in 1959 and still sees limited use in the US military. It has a 7.32 caliber bullet and a 20 round capacity. A clear improvement over the M-1 Garand. In present day, the 7.32 caliber is only capable of penetrating low level armor and is clearly not good enough to conduct modern warfare with outside of the most backwards places on the planet.

Third generation of US standard service rifle:

The M-16. Entered service in 1964 and is still in service. It fires 5.56 caliber bullets and has a 30 round capacity. Again, a clear improvement over its predecessor, with stronger bullets and a larger round capacity. Again not a good enough gun to participate in war with a US unit as the US soldiers have body armor that is capable of handling a 5.56 caliber bullet from an M-16. The gun would still be decent enough to conduct war against the average middle eastern country as long as it's not used in fights against special forces whom we can expect to be better armored.

Fourth generation of US standard service rifle:

The M4A1. Been in service since 1994. Also uses 5.56 caliber bullets and has a 30 round magazine capacity. Which means on the face of it this gun is similar to the previous generation and the gap between the M-16 and the M4A1 isn't as clear as that between the M-16 and the M-14. The primary advantages provided by the M4A1 over the M-16 can be found in the smaller details. The M4A1 is lighter, more compact, easier to use in close combat, while having adjustable and collapsible components that were fixed on the M-16. While being on the wrong end of the M-16 or the M-4 you would not be able to tell the difference, but being on the right side of the gun, you would be able to find a greater ease of use in the M4A1 which acts as a clear advantage.

Fifth generation of US standard service rifle:

The XM7 was active use by the military in 2023 and is expected in time to replace the M4 rifle as the standard service rifle used by the US military. The XM7 uses 6.8 x 51 mm bullets and has a bullet capacity of 20 bullets which feels like a clear downgrade form the previous generation of military rifles. The XM7 is also far heavier than the previous generation of rifles. So we really have to ask, how is the XM7 better than the M4?

The only real answer appears to be the bullets used. The XM7 when used, is capable of shredding through even the highest grade body armor available on the market. Which means that there is no real protection against the XM7 if it is fired at the enemy combatant. Meanwhile the armor available to the US military is capable of handling the bullets shot by the rest of the world's military rifles. This ends up giving quite a clear advantage to the US army in a firefight.

As we can see based on all of the above information, most people do not realize that the military rifle has been constantly evolving quite rapidly. With each generation of soldiers getting a better gun than the previous generation to use on the field. Today, the arms race between more powerful guns and better body armor has been won in favor of the XM7 rifle and nobody is safe from the pain that comes with getting that rifle fired at you.

Now the final question that comes to mind is, what will the next generation of the US rifle look like after the XM7? While we cannot know all of the details, some features we can be certain about. The next generation of standard service rifles which we can expect in the 2040s-50s will almost certainly maintain a bullet capacity of 20 or go back to 30, as going below 20 isn't an option in a firefight. They will have to be lighter than the XM7 as the XM7 is already considered on the heavier end, and they would very obviously have more powerful bullets than the XM7. The next generation service rifle will obviously be a natural progression of the XM7 without all the limitations the XM7 developed over the M-4, which means a lighter, more compact, and more convenient gun.

Conclusion:

The modern day rifle is extremely overpowered against unarmored targets and without body armor of the highest caliber you have zero chance of succeeding in any conflict against a trained US military squad. Even with the highest caliber armor they will win because they can still shoot through that armor. Rifles continue to evolve every 20-25 years with every generation of humans getting a better rifle that is a clear upgrade over the previous one. Energy weapons will likely never replace the bullet as its simply easier to make more powerful bullets than to 10x the energy output of an energy rifle every time better armor shows up on the battlefield.