for a SHTF rifle, reliability is more important than having a whole bunch of adjustments

Go to the dark side.....

Get an AK.   

Pick up talula's bull pup sks in the classifieds for $650 then build or buy your dream AR for $2K.

Bam, mission accomplished.  Bull pup, Ak platform and AR.

P.s.
I thought a 16" barreled AR was effective out to about 300 yards velocity wise (enough velocity to get the yaw and fragmentation)
I am not in the military nor a lawyer.

P.s.
I thought a 16" barreled AR was effective out to about 300 yards velocity wise (enough velocity to get the yaw and fragmentation)
I am not in the military nor a lawyer.

I don't know about all these generalizations that a certain caliber is not effective out to xx yards.
If I've been hit with a .223/5.56 at 300 yards I'd go down and yell for a medic. I won't ask if it was a 16" or 20" barrel. One hit in a large artery and a person will bleed out.
Any first hand accounts of what it is like to be hit with a certain caliber at a certain distance? Those are the people I'd like to hear from.

I don't know about all these generalizations that a certain caliber is not effective out to xx yards.
If I've been hit with a .223/5.56 at 300 yards I'd go down and yell for a medic. I won't ask if it was a 16" or 20" barrel. One hit in a large artery and a person will bleed out.
Any first hand accounts of what it is like to be hit with a certain caliber at a certain distance? Those are the people I'd like to hear from.

This looks pretty well thought out  ...  even though the author doesn't mention ever being shot by any caliber bullet including the 5.56/.223 variety!   

Effective Range of Your 223 or 5.56 Rifle

In this post I'm going to discuss the maximum effective range of the most common bullet weight and type, 55gr full metal jacket (FMJ).  As many people
know the standard 55gr full metal jacket projectile's primary wounding capability comes from fragmentation.  There is wounding performed by
hydrostatic shock as well, and of course the path of the bullet.  If a bullet itself hits a major blood vessel or vital organ it can of course be lethal. 
But when a bullet expands or fragments it greatly increases both the wound channel and the potential to damage something vital.

Most experts suggest the necessary velocity to ensure reliable fragmentation is 2700 fps.

16", the most common barrel length sold in AR-15 carbines and the shortest length available for general sale, gives us a muzzle velocity of of 3125.
Fragmentation range extends out to just over 100 meters, not much longer than the 14.5" barrel.

The second most common barrel length for AR-15 rifles is 20".  The M193 round gets 3250 fps and a range of right around 150 meters. 
This gives us a 50% increase in effective range over the 16" barrel.

All of these calculations were done around the military spec M193 5.56 NATO cartridge.  If instead you use .223 Winchester ammo offered by Winchester,
Remington, PMC or other companies, your velocity could be 100 fps lower than M193, as .223 is loaded to a lower pressure than 5.56 NATO.  If you
are using Wolf, Brown Bear or Silver Bear .223 ammo, your velocities could be 150 fps slower.  That can reduce effective fragmentation ranges effectively. 
Using steel cased Wolf .223 ammo in a 11.5" short barrel rifle gives almost no fragmentation capability.

In no means is this an attempt to talk people out of using 55gr ball ammunition for defense.  It is an ideal cartridge for defensive work, especially in residential
areas where light obstacles (like interior walls) will cause it to fragment very quickly and reduce the chance of missed shots striking or hurting unintended targets. 
But if it is the ammo you chose to use, you should understand it's capability.  Once you extend past it's fragmentation range, you are likely better off using another
ammunition type.  For instance, the 55gr TSX bullet made by Barnes should offer reliable expansion down to 1,800 fps.  This extends the range quite a bit at which
it offers good terminal ballistics.  A reasonable person could practice with 55gr FMJ ammo and use the TSX bullet for hunting or defense to extend your effective range.

http://angry-peasants.blogspot.com/2012/08/effective-range-of-your-223-or-556-rifle.html

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If the discussion is now AK vs AR, go with the AK.

Standard AK ammo is 123gr, while AR ammo is 55gr.  One of the main objectives of adopting the NATO 5.56 cartridge:  it weighs less than half that of .30 caliber sized AK and .308 rounds, allowing troops to carry at least double the number of rounds based on weight.

So, while the standard for NATO/US forces is 5.56, that doesn't mean it's the best choice for all possible situations. 

For SHTF, the AK will have almost the same effective range as an AR15, assuming the accuracy of the AK you have is good.  The  terminal velocity of the AK is similar to a small handgun caliber with non-expanding ammo.

In battle, the general opinions I've read say the M16 is better than the AK for longer range accuracy (within the effective range of that barrel's length).  But the AK proved more lethal once the fight was up close and personal, due to the one-shot-kill effectiveness of the 7.62x39 round compared to the NATO 5.56x45 round.

Based on the overall effectiveness, the lighter 5.56 allows you to carry more ammo than the AK ammo .... because you are probably going to need more!! 

Then there is the argument that the AK will keep firing without cleaning for next to infinity, while the DI AR15 needs to be cleaned whenever you take a rest break!  Reliability under less than ideal conditions might be another factor for choosing the AK.

With a 20" barrel, effective range is around 200yds (before the bullet slows down so much that it doesn't do much damage)   With a 16" barrel, it's more like 50yds.  This isn't an accuracy issue (if anything, shorter barrels are more accurate). it's a velocity issue.

Allow me to be the first to call bull$#!t on this.

Anyone who tells you that the effective range of a 5.56 or 7.62x39 rifle is 50 yards is absolutely idiotic.

I am willing to bet you my house that you can stand up at 300 yards and I can use my 16" AR/AK/SCAR/Tavor with iron sights very "effectively."

Well beyond your purported 50 yards or 200 yards.

With a 16" barrel, it's more like 50yds. 

WTF? We all need to hear your rationale on this one. 

Allow me to be the first to call bull$#!t on this.

Anyone who tells you that the effective range of a 5.56 or 7.62x39 rifle is 50 yards is absolutely idiotic.

I am willing to bet you my house that you can stand up at 300 yards and I can use my 16" AR/AK/SCAR/Tavor with iron sights very "effectively."

Well beyond your purported 50 yards or 200 yards.

Yes that is bullshiot!!!

This looks pretty well thought out  ...  even though the author doesn't mention ever being shot by any caliber bullet including the 5.56/.223 variety!   

Effective Range of Your 223 or 5.56 Rifle

http://angry-peasants.blogspot.com/2012/08/effective-range-of-your-223-or-556-rifle.html

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Fifty Cent was shot NINE times



GGG UNIT!

Das why I said fo' get bohf!!!

Seriously though, quality ARs and AKs can both be had now, at discounted prices.

Why not get both?

You will have two rifles (versus just one), and you'll be able to become familiar with and proficient in the use of both the AR platform in .223/5.56 and the AK platform in 7.62x39.

Again, just my opinion. 

+1 Just get both 

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That's bullet fragmentation range. Not effective range given a barrel length and round type.

That's bullet fragmentation range. Not effective range given a barrel length and round type.

Hmmm?  I thought for a firearm to be "EFFECTIVE", it needed to inflict a wound adequate to disable the target.

If you read that article again, if specifies "As many people know the standard 55gr full metal jacket projectile's primary wounding capability comes from fragmentation." 

Therefore, the round's effectiveness is directly related to the 55gr 5.56 bullet's ability to fragment after impact:  effectiveness = wounding capability = fragmentation

Fragmentation is not the only means of wounding, as the article also states, but the PRIMARY wounding capability of the 5.56 round COMES FROM FRAGMENTATION.

With fragmentation being the desired effect when the bullet strikes the target, the effective ranges listed in the article ARE the maximum distances you can shoot a standard AR-15 round (M193) through a variety of barrel lengths while still achieving adequate fragmentation.

In this post I'm going to discuss the maximum effective range of the most common bullet weight and type, 55gr full metal jacket (FMJ).  As many people know the standard 55gr full metal jacket projectile's primary wounding capability comes from fragmentation.  There is wounding performed by hydrostatic shock as well, and of course the path of the bullet.  If a bullet itself hits a major blood vessel or vital organ it can of course be lethal.  But when a bullet expands or fragments it greatly increases both the wound channel and the potential to damage something vital.  It's a morbid topic, but if you use a firearm for hunting or defense, you want it to be effective, so it's an important discussion.

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There is some good stuff here, but some very misinformed comments.

Building is a plus and a minus.  With current costs, from a financial standpoint building does not make sense for your average person at this time  Even for those who may get discounted pricing for various reasons, even pricing direct from the factory to their factory armorers, building a base rifle is still not a big savings over current pricing.  Now if you want the satisfaction of doing it yourself despite costs, go for it.  Do your research first.  Yes this rifle is one of the easiest platforms to assemble, but those who say it is as simple as lego's are somewhat correct but generally misinformed. 

Since the AR/M4 shares commonality of parts it simplifies the process.  If you use quality parts with good build technique then most often then not, you are good to go.  Lesser quality parts can be problematic which are often the result of a "tolerance stacking" issue.  If you do have an issue, trouble shooting is more difficult for those who are new to the system.  I might suggest m4carbine.net to do research if you build.  Read, read and read more.  Then if you have questions ask.  The members over there are helpful to those who have already attempted to help themselves by doing their own reading and research.  They are less forgiving to those who want everything spelled out in their own thread.  Most answers can be found by searching.  You can try ar15.com but too much BS there.

I personally build all of my own rifles because I do a lot of gun work professionally and I am heavily experienced on this particular platform.  I get the right pricing, have all the tools and have been doing it for a long time.  I pick and choose what parts I want from the start, so there is no need for a base rifle and then upgrading it.  Quite frankly I build a better rifle than I can buy.  However for most individuals a quality base rifle and upgrading is more often the way to go.  Or the next step as mentioned is buying the complete upper and putting together the lower. 

Torque values are important but not a huge issue for those who work around torquing things all the time.  The barrel torque does matter for accuracy.  Over tighten a barrel nut and accuracy can diminish and I am not talking about over torque as in beyond the 80ftlbs, I am talking about a torque spec that still falls within milspec values but can diminish barrel accuracy.  There is a good range of torque value that we find is more conducive to accuracy.  Over torque a muzzle device and you might again screw up accuracy by "trumpeting" your muzzle end.  There are quite a few things that most experienced DIYers or even most factory trained armorers do not understand.  Small things individually can be, well small, but stack them up together and they can be a big deal.  Good or bad.   

The .223 / 5.56 bullet efficacy quoted in this thread is not exactly correct or more so does not tell the entire story.  The fragmentation topic discussed here and linked in this thread is in regards to statistics on FMJ rounds and at which velocity fragmentation occurs.  These numbers vary greatly when it comes to soft point or various rounds that are built to induce expansion perhaps via hydraulics or impact deformation.  We should understand that fragmentation and penetration are 2 very different topics.  The #1 consideration on efficacy of a projectile is penetration first and foremost above any other considerations.  If the round and the fragments do not have the ability to reach or pass through vital blood bearing vessels then it is nowhere near as effective.  Fragmentation is only beneficial if penetration is correct.  Of course if you can get both, better yet. 

Think of it this way.  If you get shot with a .308 in a soft blood bearing organ, not a CNS disruption and it goes through and through and the same with a .223/5.56 that goes through and through, the size of the hole difference is not so great.  Anyone who want to start quoting permanent vs. non permanent wound cavity, hydrostatic, kinetic energy, save it.  In other words, just because a .223/5.56 does not fragment but still penetrates correctly, that is what we want.  Expansion and fragmentation is only a bonus which was a plus for that round, but not a necessity.  We have been proving that well for the last decade plus. 

Is it the best in long range engagements?  Not by any stretch.  Is it the best at short range?  No, but it is a very good all around caliber out of a weapon platform that is reliable, shoots with ease and is accurate at long range.  Anyone who questions effective range, I was shooting 18x30 steel at 920 yards pretty easy.  What was the ballistic efficacy of the round at that distance?  Not sure, but I can say 100% that I wouldn't want to get hit with it and that it would probably ruin your day, your week, the month, year or the rest of your life.

Hmmm?  I thought for a firearm to be "EFFECTIVE", it needed to inflict a wound adequate to disable the target.

If you read that article again, if specifies "As many people know the standard 55gr full metal jacket projectile's primary wounding capability comes from fragmentation." 

Therefore, the round's effectiveness is directly related to the 55gr 5.56 bullet's ability to fragment after impact:  effectiveness = wounding capability = fragmentation

Fragmentation is not the only means of wounding, as the article also states, but the PRIMARY wounding capability of the 5.56 round COMES FROM FRAGMENTATION.

With fragmentation being the desired effect when the bullet strikes the target, the effective ranges listed in the article ARE the maximum distances you can shoot a standard AR-15 round (M193) through a variety of barrel lengths while still achieving adequate fragmentation.

All I have to ask is how many people have you shot with a M4?  23 years in the Army, 3 wars, and 5 deployments says you can put an enemy down at greater than 50 yards with an M4.  I have done it myself. You can internet speculate all you want and read someone else's science experiment and maker your own decisions.   

All I have to ask is how many people have you shot with a M4?  23 years in the Army, 3 wars, and 5 deployments says you can put an enemy down at greater than 50 yards with an M4.  I have done it myself. You can internet speculate all you want and read someone else's science experiment and maker your own decisions.   

The article lists the effective range for a 14.5" - 16" barrel with M193 ammo at over 100 meters.  A 20" barrel get you out to around 150 meters.

So, I don't see why you are arguing against a 50m/50 yards number.  That was Crazy Cat's estimate, not the article's.

The article lists the effective range for a 14.5" - 16" barrel with M193 ammo at over 100 meters.  A 20" barrel get you out to around 150 meters.

So, I don't see why you are arguing against a 50m/50 yards number.  That was Crazy Cat's estimate, not the article's.

Even 100 yards is bad information. 150 years is bad information.  There is an effective range for the M4 weapons system.    500m