Side By Side Photos of an Aero Precision Lower and Palmetto State Lower

Anyone who’s ever considered building an AR-15 has probably gone through the hassle of selecting a “lower”. This refers to the lower receiver of an AR-15 pattern firearm. There are a million to choose from, and they all market themselves as being different or ‘better’ than others. You can read a bit about them on Wikipedia.

There are too many companies that make lowers to list out here, but two of the most popular options are by Aero Precision and Palmetto State Armory.

Lower receivers are what houses the rifle’s trigger assembly / firing mechanism. They’re the ATF serialized part of the gun, too, and so they need to be transferred via FFL (if you wan’t to be legal about it).

I’m not going to deep-dive lower receivers here. You’re probably here because you’re researching lowers, and so I’m not going to rehash “mil spec”, 7075 aluminum, cast receivers, forged receivers, billet receivers, hard coat anodizing, or the rest of it. You can find that stuff anywhere on the internet.

What I am going to share are high-res images of a Palmetto State PA-15 and Aero M4A1 Clone lower side by side from top down, left side, right side, and a close up of roll marks.

These are both 7075-T6 lowers, so the material is the same.

The Aero lower is more expensive, but you can see that the Aero has a little better machining — check the exterior and thread pattern in the buffer tube area — and features the ability to house a set screw to remove play between upper and lower receivers, which the Palmetto lacks.

I own both of these and I have no financial or business relationship with either of these companies. This is literally just a post designed to let you visually inspect two of the most popular lowers side by side.

I hope it helps in your decision making process.

Left Side Up
Ejection Port (Right) Side Up

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Top Down View
Roll Marks (Serial Numbers are Photoshopped to be different)


I’ve had both of these receivers kicking around in my safe for a while now. This is why they each have a few small blemishes. They arrived from the manufacturer in good shape, so don’t think that these companies are sending out dinged up stuff.

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