Many folks find themselves feeling overwhelmed when they decide to build their first AR. Buying a factory model first has its advantages, as it allows you to get familiar with the internal mechanical functions, which makes it far easier to understand how to assemble and tune one.

Don't let a high parts count discourage you, AR's go together relatively quickly and easily. I can put one together from parts in under an hour, and if I can do it, then there's really nothing super complicated about it.

The only important parts in an AR, in order:

1) Good Barrel (Black Hole Weaponry, White Oak Armament, Shilen)

2) Good Trigger (mil-spec + JP yellow springs + 37cent 1/4"x28x1/2" set screw, RRA NM 2 stage, or Geiselle SSA or NM 2 stage)

3) Adjustable Gas Block (clamp on style JP or BTE)

Everything else is personal preference and won't affect function.

I think a lot of folks buy 16" barrels planning on being some war movie action hero, but then quickly find themselves disillusioned about the handling.

Balance: Many folks will find that 16" barrels don't balance or handle as well in hand. They feel nice, light, and handy in the store because the center of balance is between your hands, but then reality sets in when you get to the range is that the lack of forward mass makes it more difficult to steady on target. The difference in accuracy between different barrel lengths is about stability, not about anything inherent to the barrel itself. 16" Carbines can shoot well, but by and large, all shooters will be more accurate with a bit more muzzle weight (barrel length).

Weight & Fluting: A 16" fluted barrel makes absolutely no sense unless you're talking about a .920" or .836" gas block, or just want your rifle to look fancy. Fluting is only meant to let a larger diameter, stiffer barrel weigh less - a .750" barrel is plenty muzzle light, especially a 7" carbon length gas system - and a 16" barrel is plenty stiff. The extra surface area will mean absolutely nothing for a .750" in terms of cooling. Fluting looks cool, but the functionality is nearly useless.

Power: AR's tend to give up about 50fps per inch of barrel loss. A 20" AR will run around 200fps faster than a 16". It might not seem like much, but at it's tipping point, it does tend to make a difference in killing power at range.

RIFLE weight: The difference in weight on shoulder and portability for a 16" carbine and a 20" rifle with a collapsible stock really isn't much. Stretching out to 22" or 24" - or longer - will start getting outside the frame of your body enough that it becomes a bit more unweildy. Compared to bolt guns AR's are heavy, period. You have to try VERY hard and use pencil barrels and light weight components to get a 16-18" AR to weigh as little as a 24" bolt rifle.

If you want a CQB Entry rifle, slap on a carbine stock, never open it, stick your nose on the charging handle, learn to shoot with a ~9" LOP, slap on a 16" barrel, and go spray surplus ammo at nothing all day. If you want a versatile rifle, get a different barrel length.

In general, my experience has been that an 18" or 20" barrel will have the ideal mix of handling/balance and power. Throw a carbine stock on it and you'll have a very portable rifle.

It sounds like you have been mislead - your comment that a barrel would get so heavy that you'd have to sit at a bench to stabilize is backwards. Again, extra muzzle weight helps shooters stabilize on target.

If you "shell out thousands [of dollars]" on an AR-15 Carbine, you've done something wrong. Great quality carbines can be bought off of the shelf or built for $500-600. Only the top end competitive rifles cost "thousands". My 5 most recent custom rifle builds have been $1000-1500, my wife's upcoming "Cadillac build" will be $1900 with no expense spared on top end components ($500 on barrel alone). Carbines are cheap.

Think about this logically - how does this make sense at all? The rifle that "does everything" will get used to DO everything, so you'll find yourself shooting it more. A rifle that only does ONE THING will end up sitting in the safe more - and frankly, I get pretty d@mn bored watching my rifles sitting in the safe.

The difference in 223rem and 5.56 Nato is highly over-rated, and is largely irrelevant for AR's in our time. The major difference is in the length of the throat, with no other significant chamber dimension differences. The pressure differential between the two is 100% irrelevant in factory ammo, and only the most irresponsible reloader will ever cross an unsafe pressure boundary with either cartridges load data. Beyond that, Almost all modern produced AR barrels are chambered for either 5.56 or .223Wylde - essentially a 223rem chamber with a 5.56 throat - so you really have to look to get a pure 223rem.

The statement that one is a 4cyl and one is an 8cyl is just foolish. 5.56 and 223wylde throats allow loading of longer and heavier bullets, but the differential in power is minimal at best. If anyone ever tells me that they notice a real difference between the two in the field, I tend to cross them off of the "knows what they're talking about" list.

The 223wylde chamber will safely and accurately shoot either 5.56 or 223rem.

You would have to selectively order a 223rem (pure SAAMI) chambered AR barrel. The point is moot.

I wouldn't ever say that my AR's are better than anybody elses, since AR's are AR's. But the practical versatility of many of my AR's is very high - they're very useful and usable rifles.

What I have found to be the most "useful" and most "practical" AR-15 is an 18" or 20" barrel with a .750" adjustable gas block in 5.56/223wylde and a heavy profile under the handguard, with a telescoping stock.

If you want a powder burner, then buy a Del-ton kit or a Bushmaster or DPMS carbine off of the shelf for $500 and go spend the rest of your money on surplus ammo.

If you want a functional and practical rifle, spend about $900 at Midway, Brownells, PSA, or Joebob Outfitters and $300 on a Black Hole Weaponry Barrel and be happy.