Indications Your Lower Parts Kit Needs Help
We hate to break your heart, but that AR-15 of yours isn’t always going to function perfectly. Whether you built your rifle yourself or purchased it as a completed piece, you can’t expect it to stay reliable forever without a little TLC. Sometimes problems arise which are outside of your control, but there are also many precautions you can take to reduce the likelihood of your firearm failing when you need it most.
Just think about all of the tiny components of your AR-15 lower parts kit. Make one error while building, reassembling or enhancing your weapon, and you’ve created a potentially serious problem.
Fortunately, appropriate placement of most lower receiver parts is fairly simple once the parts have been properly identified, because many pieces obviously fit only one way. An exception to this is the hammer spring.
If you encounter repeated misfires, bursts of fire or complete weapon shutdown, check your trigger pin to ensure it is not protruding from the side of the receiver. If you find the trigger pin is not flush with the receiver surface, it is likely the hammer spring has either been positioned with the legs somewhere other than in the detention groove of the trigger pin or that it has been installed completely backwards.
Remember, for proper hammer spring installation: Affix your hammer spring by placing he spirals of the spring over the protrusions on both sides of the hammer. The crossbar section of the spring will face the rear, and the open, straight ends of the spring will face the front. You will then insert the hammer into the lower receiver, on top of the trigger assembly. The legs of the hammer spring need to rest on the pin that is holding the trigger in place. Press the hammer down and towards the front of the receiver. Once aligned, you can insert the hammer pin through the receiver until it is flush on both receiver surfaces.
Worn or Broken Lower Receiver Parts
You are probably going to have to work pretty hard in order to wear out your AR-15 lower receiver parts, but failures do happen. Here is where you are most likely to see them, in no particular order:
Fire Control Group
The first area for breakage lies in the fire control group. A worn sear or disconnector may cause multiple rounds to be fired when the AR-15 trigger is depressed, and replacement of these parts or the entire fire control group will easily correct this problem.
If your trigger seems to be locked up, a loose trigger pin or broken hammer spring may be your culprit. While the trigger pin can be repositioned (or replaced in the event it is lost entirely), you’ll definitely need to replace a broken hammer spring. A broken hammer could also be the cause of your weapon failing to fire and would require replacement in order to resume proper functioning.
In the event your weapon fires even when the safety selector is on “safe,” prompt inspection and replacement of the selector switch is likely warranted. Sometimes the selector switch can become stuck in the “fire” position, but this problem can generally be remedied by disassembly and lubrication of the selector.
Buffer springs can degrade over time, rendering them incapable of fully driving the bolt back into battery. Without this chain of events, the bolt can’t pick up another round from the magazine. If nothing happens when you pull the trigger, or if your weapon fails to cycle the next round, you had better check on the health of your buffer spring.
In some cases, the buffer spring may have enough power to cause the bolt to push the next round just shy of proper placement, thereby requiring you to utilize your forward assist. Having to use the forward assist on a regular basis is a good indicator that your buffer spring needs to be swapped out.
If you find that your bolt isn’t being held back by the bolt catch, it is possible that a portion of the catch is either broken or bent. This typically happens due to dry firing when the weapon is broken down and the bolt and carrier aren’t in place.
Alternatively, a weakened or broken bolt catch spring will also prevent your bolt from locking to the rear after firing the last round. Installation of either of these lower receiver parts are fairly simple and inexpensive fixes.
A broken or worn magazine catch or a defective magazine catch spring will prevent your magazine from locking into your rifle magazine well. Before replacing these AR-15 parts of your lower receiver, however, ensure that the problem is not being caused by a faulty magazine itself.
Non-Lower Receiver Part Problems
Lower receiver parts are not the only pieces subject to wear and breakage. In fact, many AR-15 failures and malfunctions are instead associated with the upper receiver and bolt carrier assembly areas of the firearm. Broken bolts, worn out extractors and extractor springs, defective firing pins or firing pin retaining pins (cotter pin) and faulty ejectors are all common culprits. Loosened bolt carrier keys and worn gas rings are also lead causes of AR-15 shutdowns.
Preventative Maintenance: Inspection, Cleaning and Lubrication
Although it seems that no two firearm experts agree on how frequently specific parts should be replaced, few deny that regular cleaning and lubrication of your firearm will go a long way in staving off malfunctions on the range or in the field.
Perhaps even more importantly, the more you handle and become familiar with the inner workings of your AR-15, the more likely you will be to notice potential problem areas before they become major issues. Check for loose or missing parts on a regular basis, and stock up on common replacement pieces so they are available when you need them.