What is a High Shelf Lower and Compare With Low Shelf - Daily Shooting | Shooting Tips And Reviews

What is a High Shelf Lower and Compare With Low Shelf

When it comes to assault rifles, there are all kinds of variations with them. One of those variations comes with the type of receiver that your gun has. In this article, we will look at what the receiver is and the two different types. With receivers, you have both high shelf lower and low shelf lower.

Read on to find out what is meant by that and why it matters. Also, learn the difference between a high shelf lower and low shelf lower.

What is the receiver?

Before getting into high shelf versus low shelf lower receivers, we will look at what the receiver in an assault rifle is. The receiver is the part that holds the hammer, bolt, or other firing mechanisms.

The reason it is called the receiver is that it receives the barrel. Normally the barrel screws in.

The receiver has a raised piece of metal on the inside, and this raised piece is what is called the shelf, and it is in the lower half of the receiver which is where the lower part comes in.

Depending on the manufacturer this piece of metal can be at a low height or a high height. Depending on your intentions with your gun the height of this shelf can affect things.

High Shelf vs. Low Shelf

On a high shelf like the name implies the shelf raises higher than on a low shelf. Even though the high shelf lower is higher though, it is not substantially higher. The added metal can be measured in grams, not ounces.

The way you can tell a high shelf lower versus a low shelf lower is by looking at it.

On a high shelf lower the metal shelf will raise about even with the selector hole in the bottom of the receiver. On a low shelf lower, the bottom will intersect about half way.

It is as simple as just looking into the receiver to see if you have a high or low shelf.

What does Shelf Height effect?

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Both high shelf lowers, and low shelf lowers fire in the same way.

The height of the shelf normally doesn’t affect any way of how the gun functions. The shelf height also normally doesn’t have any effect on what trigger you can use. If it doesn’t affect the way the gun functions or even the trigger, then you may be wondering what it does the effect.

Well, the answer is it affects how easily you can install an RDIAS. An RDIAS is a Registered Drop in Auto Sear. The name still might not tell you what that is though. An Auto Sear is an accessory that will turn your gun into an automatic rifle, instead of semiautomatic.

The reason that the gun manufacturer may not want you to install this is in most areas automatic weapons are illegal or heavily regulated.

The manufacturing making it so you can’t install an RDIAS covers their butt for liability purposes.

The thing is a high shelf lower doesn’t stop you from converting your gun to an automatic if you want to. It just makes it harder.

You can buy RDIAS that are designed to go onto high shelf assault rifles.

Also, you can mil the drop in part to make it shorter and allow it to work in your gun. By the way, if you are using an AR-10 rifle, the best scope for AR-10 is the good one you should had.

Which to buy?

So, which type of shelf should you buy? Well, if you want to add an RDIAS, then it is best to start with a low shelf because it will save you the headache of having to customize the RDIAS, but if you don’t plan to add one to your AR in the near future, then it really doesn’t matter what receiver lower that you buy. You should buy the AR that you like and is in your budget. If it ends up being a high shelf and you want to add an RDIAS later, then you still can with some customization.


So, now you know what is being talked about when you hear high shelf lower versus low shelf lower. You also now know the differences between a high shelf lower and a low shelf lower. You know that the shelf that is being referred to is the lower part of the receiver. You also now know more what the receiver does and what the lower shelf height effects.

You know that on a high shelf lower it is harder to install an RDIAS, but it can still be done. On a low shelf lower it is much easier however to install an RDIAS. You also now that an RDIAS is how to convert your assault rifle into an automatic. Now the confusion of a high shelf lower versus low shelf lower should be cleared up for you.

Daily Shooting Team

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