What’s the Difference Between Semi Auto vs Full Auto Bolt Carrier Group?

We have been asked about this many times that is the difference between semi auto vs full auto bolt carriers. There is a lot of noise about this and we understand what confuses you. This is why we have composed this post and thought of taking all the guesswork out of this.

Differences Between Full Auto Vs Semi Auto Bolt Carrier

Remember the bolt carrier group (BCG) happens to be an important part of your gun. It contains the gas rings, firing pin, ejector, and extractor. A real good BCG is worth its weight in gold and this is why you should invest in it carefully.


To put it simply, an AR 15 semi-auto BCG does not have a full-auto lug. This makes it lighter and is easy to fire with, technically speaking. Since it is a simple machine, you can say that it is easy to use too. It is a cleaner option for all these reasons and this means it does not jam that very often.

In spite of this, we have to agree that there is a lag that needs it to be locked before firing the next shot. This certainly makes it safe, but this is a pain in the wrong place for sure. This is exactly why we have listed the pros and cons of this type of BCG in this post. It will help you make that decision.

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Has a smooth working cycle

The cycle is faster

Is light in weight

Impressive leveling

Improved accuracy


Has a high recoil


We have to add this one comes with a full-auto lug and that makes all the difference. This helps the gun to fire whenever the trigger is pulled. The lug gets into contact with the sear and that causes the action.

If truth be told, then we have to agree that it is the heavier of the two. This is one reason why fully automatic weapons come with a lot of safety measures. There are state laws in place that need special protection if you plan to invest in an M16. You must abide by them and procure a fully automatic with caution.

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Expect low recoil

Automatic firing means less stress on firing

The carbine does not wear down that easy

Better accuracy


Anticipate slower cycles

The Main Differences Between Semi-Auto And Full-Auto BCG

We have already mentioned a few differentiations between the semi-auto and full-auto bolt carriers in this argument about semi auto vs full auto. Since we want you to make an educated decision, so we are referring to all variations that you need to know about these two. Below is a categorical explanation of the two.


Hands down, the fully automatic BCG is more dependable. It is heavier, has a longer barrel, the cycles are slower, and the recoil is low. What more do you want in a gun to make it secured?

Again, if you prefer lightweight firearms, then you may think otherwise. An AR 15 semi-auto BCG lets you keep your hands rest on the firing position, which means you are always ready to fire. Think of a hunting scenario, where you can save time.


We have cited this earlier that full-auto is heavier than the semi-auto. Now, we can only cite that owing to this weight a fully automatic BCG is more stable, can reduce the damage, and has lower recoil as compared to the semi-auto ones. A semi-automatic BCG can be lighter in weight but lacks these features for sure.


So, the truth is semi-auto and full-auto bolt carrier groups are compatible with standard rifles. Yes, you heard it right as they can fit into the kit, buffer, lower, and upper receiver without difficulty. You can use them interchangeably and enjoy your shooting.


Speaking of availability, then we have to concede that full-auto BCG is a more viable option these days. They are easily available in the market and semi-autos are a rare find nowadays.


As discussed in the previous sections, a full-auto has an additional lug attached to it. This makes it heavy, stable, and accurate. While a semi-auto lacks this lug that can keep auto-sear the weapon after getting triggered.


A semi-automatic rifle is shorter than a fully automatic one. The lug that we keep bringing up is the reason for this. This is why the two have different profiles as they need to fulfill the requirements they are supposed to.


Which One Should I Go For Among The Semi-Auto And Full-Auto Bolt Carriers?

Ans. Your prerequisites pretty much define which one will suit you. If you want something lighter, then the AR 15 or semi-auto BCG should be fine for you. M16 is the compliance of the industry at the moment. We say either one is good for you, provided you get it from a name brand.

Are Full-Auto Bolt Carriers Legal?

Yes, they are legal, but there may be laws in your state particular to the use of these weapons. It is advisable that you go through them once and then upgrade your rifle.

The Verdict

If you ask us, then we would say that both semi-auto and full-auto firearms are good. They are secured and will fire shots, unless you upgrade them with fully automatic parts. If you are a hobbyist, then it will hardly make any difference. You can go for either of them, but if you are a professional, then things will be different.

Honest, confession here, we favor the full-auto bolt carrier as we find it more durable. In addition, they are a good choice keeping future upgrades in mind. It certainly adds some weight to your gun and is also easy to use. All this makes it a reliable resource for firing shots whenever you want.

Shane Watson is a Co-Founder veteran. He had served the forces for years and that makes him quite an expert. His years of handling guns of all kinds made him not only a gun enthusiast but a thoroughly experienced one too!

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