Preface: The modern consumer AR15 is an amazingly diverse system. Besides its storied history, one of its main attractions is its modular design. Almost every part of this weapons system is easily replaceable. No other platform has as much aftermarket support in the market today. It can be configured as a long range precision instrument, or a close quarters combat (CQB) pistol or short barrel rifle (SBR). It can be chambered for a wide range of calibers from the venerable .22lr to a .50 Beowulf. Early AR15s and their M16 counterparts are 20” rifles. The majority of AR15s in the commercial market today are 16” or shorter “carbines”. Extremely strong aftermarket support, and standardized parts interchangeability make this platform extremely popular with many consumers. However, since there are so many configurations, many new consumers are overwhelmed with the choices that they face. To address this, I’ve written this document to help the first time consumer become an informed consumer. A little knowledge goes a long way to help you spend your hard-earned money. My sole wish is to provide you with enough background and general information to make a smart buy, and I will try to remain as objective as possible. I would also like to say that this is a general overview and I will not go in depth with every explanation. I do hope that after reading this, you come away with a good understanding and appreciation of the AR15. I would also like to give thanks to my friends Dieselpower from Calguns.net, and Quentin from Firearmstalk.com for their help and suggestions. Special thanks to my good friend and cousin Connie for her time and effort in making sense of my incoherent ramblings. A brief history: The AR15 was developed in the 1950s by Eugene Stoner as a lightweight 5.56x45mm version of the AR10 7.62 NATO. The first AR15 was made in 1959. It was intended to be a lightweight rifle that shot a lightweight round, so that infantrymen could carry more rounds per loadout when going into battle or patrol. More historical information can be found here: http://en.wikipedia.org/wiki/AR-15 Nomenclature: The modern day civilian market AR15 is a semi automatic firearm. The original AR15 was a select fire (automatic) weapon that was intended for military use only. Please be aware that AR15s marketed as an M4 are not truly M4s unless they have select/automatic lower receivers with automatic fire control groups, and 14.5” barrels with carbine gas systems. M16s are also select fire/automatics with 18” or longer barrels with rifle gas systems and usually a carry handle on the upper receiver. Unless you are in a state that allows NFA gun ownership, and you are willing to wade through and then wait for all the paperwork to process, you will not be able to get an authentic automatic M4 or M16. Everything else is an AR15, no matter what’s stamped on the receiver. Figuring out which AR is the best for you. First question you should ask yourself is: “How am I going to be using this rifle.” Your “intended use” will govern what style and what options would be more important to your choice. It should include what kind of shooting you intend to do, and at what distances. If you live in the city and can only shoot at a rifle range, you will be limited to the distances available at your range. If you want to use this gun to shoot prairie dogs at 500 yards, then your choices may be vastly different compared to the intended use for home defense. Put simply, if you want to target shoot at 1000 yards you can do it, but its not going to be the same AR as your home defense rifle. Second question you should to ask yourself is: “Do I buy a complete AR or make one?” This is a purely subjective question. I feel that if you are comfortable fixing a bicycle or assembling Ikea furniture, you can build at least the lower receiver by yourself,. It’s really not that difficult. You will get the added benefit of learning the inner workings on how your AR works. It is just a simple machine. There is nothing mysterious about it. Installing a barrel on the upper receiver is a bit different as it requires more specialized tools, but if you opt to build your own lower receiver and purchase a complete upper receiver you may be able save yourself some money. You will learn a lot about how your gun functions, and you will be able to choose every single component in your rifle. Purchasing a complete rifle is a valid choice, and many people do choose to go this route. The main benefit is that you don’t have to spend any time putting it together and it comes with a manufacturer’s warranty. (Keep in mind though, if you want warranty work done on it, you most likely will have to ship your rifle in and will be without a firearm.) Competition is pretty fierce nowadays, so if you shop around you can find an AR15 complete for pretty much the same price if not cheaper than what you can build it for. My personal recommendation is to purchase a stripped lower from a local guns store (LGS) and then purchasing parts online and looking for the best deals based on exactly what you want. I also personally try and purchase locally as much as possible. If the price difference is under 10% I will generally purchase locally. You may or may not decide to do the same but it’s nice to have a gun shop close by. Again this is my personal preference; please don’t take this as something you must do. Choosing the right option! The main factors that you should consider in your decisions are: need, weight and cost. To increase your happy quotient, make choices to maximize meeting your needs, while minimizing cost and weight. Remember, every choice you make, entails tradeoffs: Cost, precision, weight, reliability, utility. Keep this in mind when you making your decisions! One important rule of thumb! Weight is the enemy! You can hang every possible gizmo and gadget on your AR and have one blinged out, super sexy, radical tactical, ultra mall ninja 15 pound beast! Or you can have an AR that weighs just 7 pounds and does everything you need it do. General types of AR15: M4gery: The most common AR15 would be the M4 type 16” barreled carbine, affectionately known by many as the M4gery. It is modeled after a standard issue military m4 carbine with the exception of a mandated 16” minimum overall length barrel and semi automatic fire controls. It can come with carry handle type upper receiver or a flat-top upper with a 1913 rail. It features a collapsible stock and a non-free floated seat of carbine length hand guards. This style is very popular, and is good for most types of shooters. Range shooting, plinking, varmint hunting, competition, home defense, and service (law enforcement/military) types all use this style. It features a carbine length gas system (7” gas tube). This is the type you most commonly see in t.v. or movies. It is what most people think of when you say M16 or M4. If you are interested in just general use/plinking under 300 yards, this is the type that is the cheapest and most readily available. With a decent barrel and decent ammunition, a good AR give you to 2-3 MOA (2-3” inch groups @ 100 yards). With a great barrel, match grade ammunition, and a good shooter, you can expect 100 yard groups easily be 1 MOA and under (one inch groups @100 yards). I would generally recommend this type of AR15 for most shooters, with an exception of the gas system. I personally prefer mid-length gas systems; I will expand on this later. Long Range Precision / Varmint types: If you are opting for a more specialized use that requires more precision than your average AR, this is the type of AR you should be looking at. These ARs are precision-oriented and make tradeoffs on cost and weight to achieve greater accuracy and precision. Usually the first thing that separates them from M4gerys is the barrel. In this instance, a longer barrel is chosen with different twist rates and made from different materials. Varmint types might even have slower twist rates which are optimal for shorter/lighter projectiles used for varmint hunting. The second thing that sets them apart is choice of hand guards. Precision-oriented builds will all invariably have free floated hand guards. This means the hand guards (whether tube type or railed type) do not touch the barrel throughout the entire length of the barrel. It floats around the barrel and is only attached to upper receiver or sometimes the barrel nut. Having the hand guards free floated allows your rifle to be more consistent as it protects the barrel from any pressure and movement that may change your point of impact. Beside any aesthetic preferences, hand guards can add a little weight and are usually more expensive than your average plastic hand guards. Stocks for these builds are usually bigger and adjustable to provide better check weld, stability and balance for these heavier styles. SBR/Pistol builds: For the sake of brevity, I’m only going to touch upon these types of AR15. Please check your local laws as to the legality of ownership of these specific models. These types are generally suited for close quarters use (less than 100 yards). I personally love these types of ARs but there are tradeoffs you must consider when purchasing them. First off is cost of ownership. SBRs (short barreled rifles) are any rifle with a overall barrel length shorter than 16 inches or has an overall length of 26 inches in length with the stock fully collapsed or folded. You must file paperwork and wait upwards of 2-4 months, and then purchase a tax stamp in order to legally own an SBR. Pistols don’t require this paperwork but may have additional restrictions that you must research in your state. This may seem a lot of hoops to jump through, but when you are done you will have a shorter lighter weapon that handles much better, and lets you track and transition much faster. There are drawbacks however. The main disadvantages are decreased muzzle velocity and increased muzzle blast (noise and flash). Competition builds: Since this guide is for a beginner, I will only briefly explain this type of AR. A competition model is a highly specialized AR that is designed to give any the user any advantage of speed and accuracy. They vary in length and twist to compliment what the user needs. They are usually made with a specialized trigger (light and short) and specialized optics. I usually don’t recommend this type to any first time AR owner as they are usually very expensive and very specialized. At this point, you should have a general idea on how you plan on using your AR. I recommend that once you figure out your intended use, and then start looking for a barrel that will suit your needs.