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The Cam-Lock lower receiver is designed to meet some of the basic complaints people have about mil-spec AR-15 receivers, while also improving the shooter’s accuracy and precision. We are the Home of the World’s Tightest Receivers.

We believe these receivers to be some of the best in the industry, and the Cam-Lock system is an important part of the current and future development of the AR-15 platform. Let’s take a look at the benefits offered by these lowers, and how they can improve your rifle.

Importance of Accuracy and Precision

Accuracy & Precision

The terms accuracy and precision are commonly used interchangeably, but they have different meanings.

Accuracy is how close a value is to its true value.

Precision is about consistency or repeatability.

How do these terms apply when target shooting? You can be either precise or accurate, both, or neither.

  • If your shots are all over the target, away from the center, your shots were neither accurate nor precise.
  • On the other hand, if your shots are scattered across the target, but generally circle the center, your shots were accurate, but not precise.
  • If you’re shooting and get a tight grouping, but it’s not at the center of your target, your shots were precise, but not accurate.
  • Finally, if you’re getting a tight grouping in the middle of the target, your shots were both accurate and precise.

Both accuracy and precision are goals for most of us. An accurate firearm with Cam-Lock technology paves the way. Recreational and other types of shooting are a lot more fun when you’re doing it well.

Shooting competitively raises the stakes – you need to be both accurate and precise to score well, and often you need to be both of those things in a time crunch as well, making things even harder.

Shooting against the clock and your fellow competitors can quickly show you all the little things that are holding you back, even something as small as a misalignment between your receivers and some slop in the fitment of your rifle that you never noticed before.

This is why you see serious competitive shooters rolling with high-end custom rifles with precision-mated receivers, match-grade barrels and triggers, and highly-personalized optic setups that are way beyond the cost of what most people are willing to shell out.

Of course, performance at the range and on the competition field isn’t the only reason that we demand accuracy and precision from our shooting. Accuracy and precision can also be extremely important for safety reasons.

For one, if you’re in a defensive shooting situation, being both accurate and precise ensures that every round you shoot goes toward stopping your attacker. If you’re missing either accuracy or precision, you will miss out on some or even all chances you have for effective hits.

The goal of any reasonable person in a defensive situation is to stop the threat as quickly and effectively as possible. Spraying wildly will not  accomplish that, and it could also potentially land you in legal hot water.

Accurate, aimed fire is the name of the game in any kind of combat or defensive scenario, and working toward being able to pull that off under pressure is a reason why many of us burn through hundreds of dollars of ammo training at the range and seek out the best AR-15 lower receivers that deliver results.

Furthermore, each shot that misses your target has the potential to hit something, or worse, someone. Shooters have the responsibility to avoid injuries to bystanders, even in situations where we’re defending ourselves.

Issues of Loose AR-15 Lower Receivers

A loose AR-15 receiver can impact both accuracy and precision, but not in the way that many people think.

There’s a lot of discussion online about how a loose or wobbly receiver impairs an AR’s ability to shoot accurately or precisely. One study has shown that bullets exit an AR’s barrel before a loose receiver has the opportunity to impact the bullet’s trajectory or ballistic performance. However, everything must be in alignment for the projectile to leave the barrel in as concentric a flight path as possible within the firing group. In reducing the tolerance issues inherent to the AR-15 platform, a tighter fit can reduce the minute of angle (MOA) from the normal 1 to 2 MOA to .375 to .75 MOA.

Shooters, on the other hand, aren’t exempt from being impacted by receiver wiggle, though indirectly. A loose receiver can be distracting for some shooters and that distraction can lead to less accurate and/or less precise shooting.

As we discussed above, those problems in accuracy and precision can lead to less success in competition, serious safety risks when shooting defensively, and just a less enjoyable time when shooting recreationally.

Unfortunately, loose receivers are a natural result of one of the very things that makes AR-15’s extremely popular: the platform’s mil-spec design.

Military specifications include a range of tolerances so that parts can be made to fit together. That allows upper and lower receivers to fit together nicely even if they were made by different manufacturers, but it also means that they may fit very tightly or, more commonly, quite loosely.

A matched upper and lower from the same manufacturer can definitely help with this, especially from a manufacturer that is focused on precision machining, but we’ve seen factory rifles from high-end manufacturers that still ship out with a huge amount of slop between the receivers.

Fortunately, a loose AR-15 lower receiver isn’t something that you just have to live with.

The U.S. Arms Company Cam-Lock Lower Receiver

Cam-Lock Lower Receiver

The U.S. Arms Company Cam-Lock Lower Receiver is the best AR-15 lower receiver out there for shooters looking for the best fit possible. By aligning the entire bolt carrier group with the bore of the rifle and designing the bolt carrier tilt for optimal performance, the Cam-Lock system enables shooters to realize the .375 to .75 MOA mentioned above.

The AR-15 lower receiver prevents wiggling through its Cam-Lock system. This system works by mechanically locking together the upper and lower receivers so that the upper can’t move independently from the lower.

This is more effective than wedge systems that are commonly used by other lower receivers or as a bandage between a wobbly upper and lower. Wedge systems work by pushing the receivers apart and filling space in between them. However, this can push the receivers out of alignment.

Testing has shown that the Cam-Lock system provides a minimum improvement in accuracy of up to 40% when compared to mil-spec lowers, which is why we lean so heavily into the importance of accuracy and precision. We think this is a great way to improve overall performance.

In addition to the advantages imparted by the Cam-Lock system, this is also an all-around great receiver. It has an oversized trigger guard built in to accommodate for shooters who use gloves and it’s compatible with all mil-spec AR-15, M-16 A1A2, and M4 upper receiver groups.

Anodized lower receivers are corrosion-resistant, fade-resistant, and easy to maintain. A variety of Cerakote options are available for highly personalizing your weapon.  The U.S. Arms Company Builder Set is a great place to start.

The U.S. Arms Company M4 UTAW Champion 5.56 Rifle

U.S. Arms M4 UTAW Champion Rifle AR-15

If you don’t want to build your AR-15 yourself, you can still get the benefits of this receiver by opting for the U.S. Arms M4 UTAW Champion 5.56 Rifle, which offers many options for experienced and new shooters to customize a weapon that is accurate, reliable, and lightweight.