There are a few different materials that lower receivers can be made out of, but the most common material is aluminum. There are also polymer and steel lower receivers, but aluminum is by far the most popular choice. Aluminum lower receivers offer a good balance of strength and weight, and they’re also relatively inexpensive.
Polymer lower receivers are becoming more popular in recent years, as they’re even lighter than aluminum lowers. They’re also generally less expensive than aluminum lowers, although there may be some tradeoffs in terms of strength and durability. Steel lower receivers exist as well, but they’re relatively rare and typically quite heavy (and thus not particularly popular for use in AR-style rifles).
There are a few different materials that lower receivers can be made out of. The most common material is aluminum, but there are also lowers made out of steel, polymer, and even titanium. Each material has its benefits and drawbacks, so it’s important to choose the right material for your needs.
Aluminum is the most common material for lowers because it strikes a good balance between strength and weight. Aluminum is also easy to work with, so it’s often the preferred choice for custom builds. Steel is stronger than aluminum but also heavier, so it’s not as popular for use in lowers. A polymer is a lightweight option that has become more popular in recent years, although some shooters find that polymer can be less durable than aluminum. Titanium is the strongest option but also the most expensive, so it’s typically only used in high-end builds.
Ultimately, the material you choose for your lower receiver is a matter of personal preference. There are pros and cons to each material, so you’ll need to decide what’s most important to you in a lower receiver. If you’re looking for a lightweight option, polymer might be the way to go. If you want a durable lower that can stand up to heavy use, aluminum is a good choice. And if you’re willing to pay a bit more for the ultimate in strength and durability, titanium is the way to go.