AR lower billet vs Forged

Choosing your AR lower

There are two ways AR Lowers are manufactured Billet and Forged.

Billet is a solid block of aluminum. This process allows the manufacturer some artistic licensing. You will generally be able to tell these by the built in trigger guard, flared mag well and very crisp lines. You will notice certain areas are built up because there is no guarantee that the billet is free from defects such as air gap, bubbles, etc. Many people confuse Billet as being stronger but in actuality it is not. What you get for the higher price tag is something that does not look like everyone else’s lower. You should also experience tighter tolerances especially when matching your upper and lower receivers together from the same manufacturer. The extra cost comes primarily from the time it takes to actual mill this from start to finish.

Forged lowers are the norm. Forging is heating the metal up and pressing it into the desired shape. This eliminates these imperfections and aligns the molecular structure of the material. By eliminating the imperfections your end result is a stronger receiver. Utilizing this process is much faster and more cost efficient by reducing the amount time on a mill. You can generally identify these because the edges are rounded and they look like almost every other one you see. When choosing this option your major discerning factors will be the forger, who finished the mill work and what I see more people making the decision is the logo. This is where it gets convoluted. Just because it has a specific logo on the side that does not determine the forger or that they actually did the finished mill work. In this day and age of marketing and branding “the manufacturer” can order the forging with or without the forge mark and may mill in house or have a production mill finish this with their logo.

If you do a little research you will find about six forgers. The most popular one is Cerro forging (key hole marking) which probably has made forging for most of “The Manufacturers” at some point. Just keep in mind the same manufacturer will change forgers from time to time for various reasons.

The simple fact of choosing your Lower and upper receivers will come down to if someone has a unique design you prefer, if the finish is what you desire (anodized, Cerakote, Duracoat Ect.}, budget, or if there is a brand you trust or believe their marketing .

Choosing between an AR15 and AR10 lower

Choosing between building an AR15 and AR10/LR308 will depend on the caliber you want to shoot. You will notice most current made lower receivers are being marked multi caliber vs a specific caliber. Part of the appeal of the AR platform is the caliber versatility. Just because the lower is marked one way does not mean you can’t shoot another caliber. Make sure the caliber is appropriate for your lower. Then all you will need is the proper magazines and upper to match.

AR-15 lower receiver calibers

I have listed some more popular rifle calibers but there are so many others to choose from it just finding the parts. You can also build pistol caliber AR 15's but to get the best results it recommended to get a dedicated lower instead of using the block system.

AR-10 and LR-308 lower receiver calibers

Again this is a small list to give you an idea. There are manufacturers making AR platforms that will shoot magnum calibers. These are ever evolving into the Modern Sporting rifle even though that look like current military rifles.