Things to Consider When Building A Reliable AR-15 Rifle

Things to Consider When Building A Reliable AR-15 Rifle
By RAR Guns

RAR Independence XRT Rifle
RAR Independence XRT Rifle

Castle Rock, CO –-( I often see articles and post explaining how to assemble an AR-15 rifle. While I find many of these articles to be very informative, most don’t touch on the details that are required to build a reliable, accurate rifle.

First, let’s examine what a reliable AR15 must be able to do. A reliable AR-15 must first and foremost fire every time you pull the trigger. Whether in a life or death situation, competition shooting, or just plinking, your weapon needs to work properly. It must also hit what you are aiming at.

One of the main reasons an AR-15 will miss fire is that poor quality parts were used. Saving a few dollars on a bolt assembly can mean the difference between a reliable rifle and one that consistently has problems.

When building a rifle from scratch, you should have a sort of blueprint. You should know what parts you are going to use from the outset as opposed to just buying parts as you find them on sale. This is not to say you have to buy all your parts at once. But instead, know what you going to buy and why you’re using that particular part.

I have seen several instances where someone bought AR rifle parts because it was cheap. This later caused problems in the rifle. One guy bought a lightweight buffer and buffer spring because it was very cheap. Upon completing the rifle, he went to the range only to find that he couldn’t get two rounds in a row through it because it was short cycling. The buffer and spring did not match the rest of the parts he was using.

You should know how and what you will be using your rifle for. This will affect what parts you use to build the rifle. For instance, if you plan to shoot steel cased ammo in your rifle, you will have much more success with a 5.56 NATO chambered rifle than a .223 chambered rifle.

You will also need a heavy-duty SOPMOD style ejection spring kit. This will ensure that you get a successful shell extraction each and every time you fire the weapon.

Consider AR Rifle Accuracy when Building A Reliable AR-15 Rifle

Ar15 Lower Parts
Enhanced AR-15 Parts

Another thing to consider is how important accuracy is. AR-15s vary in accuracy by quite a bit. They can range anywhere from ¼ MOA to 3 MOA. A lot of the accuracy obviously has a lot to do with the barrel you choose. A barrel does not have to cost $500.00 to be a good, accurate barrel. You can achieve a sub 1 MOA with a mid range cost barrel. And contrary to popular belief, a longer barrel is not a whole lot more accurate than a shorter barrel in most cases.

What you may gain in accuracy will be lost in mobility and weight.

When thinking about how accurate your weapon needs to be, consider the mission of the weapon. If it is a combat or tactical competition rifle, you probably what something you can group a lot of rounds quickly in a small area as opposed to one shot at a time in a ¼ inch hole. There are several things that can help in this area. A gas piston system will help with faster target re-acquisition as will a good muzzle break/compensator. There are several products available to modify the receiver extension/buffer tube as well that will reduce felt recoil.

A high-quality AR-15 trigger and enhanced lower parts kit can also aid in acquiring your target quickly. I don’t recommend a two-stage trigger for a combat or tactical competition rifle. Instead, I like a short pull single-stage trigger with about 4 lbs. or less of resistance.

A reliable feed is another area that needs to be addressed. There are a lot of low cost lower receivers on the market that are very good. There are a few that are only good for paperweights. A good AR15 lower should either be forged or billet. Never use a cast lower receiver. They are unreliable and weak.

A quality BCG or Bolt Carrier Group is very important to reliable feeding. This is what is going to push the round into the chamber and lock it into place. A poorly manufactured BCG will be unreliable and possibly dangerous to the operator and other friendlies in the area.

The upper receiver may or may not have M4 style feed ramps. In today’s market, I see no reason not to have M4 feed ramps at least in the chamber. One problem we see a lot is the fit between the M4 cuts on the upper receiver and the M4 cuts on the chamber matching up. An improper fit will cause miss feeds and jams. This can be corrected a couple different ways. If you’re mechanically inclined, you may be able to fix the problem yourself. If not, take your rifle to a qualified gunsmith or armorer to fix the problem.

These are just a few things that should be considered when starting to build your own AR-15 rifle.

RAR Guns will at no charge or obligation, give free AR building advice and help to anybody who wants it. No strings attached.

RAR Independence XRT Rifle
RAR Independence XRT Rifle


RAR Guns. Home of the best AR-15s in the world. We don’t just assemble parts. We measure and test each part before it is installed. Then each part is function tested to ensure proper operation. We have several AR-15 models to choose from and we also build to your custom specifications. We warranty our AR-15 rifles for workmanship for a full year no questions asked. Our AR-15 rifles will even perform with most Russian, steel cased, and polymer-coated ammo. If it breaks or has a malfunction within one year of purchase, we will correct the problem for free.

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I have seen a rash of folks putting 3 pound triggers on their SHTF rifles.
In tense and stressful situation and inadvertent tap on the trigger and away goes a round.
PLEASE use standard AR15 fire controls for arms that may be used in high stress situations.


You sound like a fudd with no trigger discipline.


This sounds as if traditional AR-15 parts just aren’t good enough. Before a person goes out and spends money on better or the best parts, they might want to try out a build with good but budget normal parts and enjoy the surprise of how well the thing fires and how accurately it hits, in spite of all the precautions to the contrary.


1st: Short stroking is usually a problem an under gassed system. A lightweight buffer and spring would help, not impede this problem. 2nd: For fast follow up shots,”split times” the original Stoner DI system is faster than any gas piston set up. This is why gas pistons are rarely used on the AR plat forms in 3-gun and multi-gun competitions. 3rd: SOPMOD style ejection spring kit is not necessary. In fact, “it can be too much” for most rifle and mid length gas systems. I recommend using a Sprinco 5-Coil extractor spring, use either the black extractor spring insert OR… Read more »


“O” rings were all the rage when the cheap seats were shooting Wolf and other trash ammo in their AR15s. Rather than FIX the problem, that is NO lacquered steel cases, they went for the “O” ring. I have been shooting an M16 since 1970-1974 while in the service and and AR15 over 35 years in competition. I have NEVER had a failure to extract or eject. But then, I stay away from foreign ammo designed to ruin your arms. Sure, of course the Russians make the BEST ammo that might be used against them or their surrogates and sell… Read more »


Okay it’s confirmed. You are DEFINITELY a fudd. You are part of the problem. Old fudds are the majority of bullshit information being spread around the gun community.


I’m no expert here, but if you have a lightweight buffer and buffer spring, wouldn’t it act as if it’s over gassed, the opposite of short cycling?



Tom Wright

So do you have a list of spring/bolts parts for upgrading an existing rifle that has a good lower, good upper, and a good barrel, along with a solid stock already? I see the prices varying widely for springs in particular. It would be nice to know which ones are the best. I imagine most are mid-grade made by a few manufacturers, but there must be ‘the most reliable’ springs out there. And bolt. Thanks.

Green Mtn. Boy

BCG’s produced by Toolcraft are some of the best and priced fairly .
As to springs Wolff produces a wide variety of reduced power, mil spec replacements and extra power sets.

I favor the Tubb line of spring upgrades and use his flat wire recoil springs in all my AR’s.

Tubb Precision AR-15 Performance Spring Pack

Tubb Precision AR-15 Performance Recoil spring


BCM BCG, SOLGW BCG, and Springco Springs.. These are the most consistantly and well made bolt carrier groups and springs for the AR system.

Matt l

I got a Anderson lower with a spa upper, every shot rolls through without any jams or problems. I’m trying to make her as accurate as possible without spending a lot.


Thank you RAR guns. m4 feed ramps fit/match is something you dont hear to much about.


Use or borrow a midwest Industries upper receiver rod to check if the barrel has been cocked in the upper receiver. Many AR rifles barrels are cocked slightly and the owners never know it. Insert this rod and if it is cocked at all you will know it..