Barrels and Rails

Now that we have a good grasp on the Lower Receiver a decision needs to be made about barrel length.

We have lots of options. Keep in mind, in Arizona you can have Short Barreled Rifles (SBR, anything less than 16 inches) as long as you have a registered SBR permit for the receiver. I have two registered SBR AR-15 lowers.

Top to Bottom - 20 inch Colt barrel, 16 inch PRI barrel, 10.5 Spikes Tactical Barrel

  
The most common barrel is the 16 inch barrel. It is a great mix of ease of use and accuracy. Too long and people complain about how unwieldy it is. Too short and you lose some of the accuracy of the 5.56 round.

I use everything from 8 inches to 20 inches depending on the event. 10.5 inches performs well at 0-200 yards but anything further out is a waste. I can't depend on a hit at anything past 200 yards. With the 16-20 inch barrels I shoot out to 500 yards. Beyond 500 yards I use a .308 or larger.

8 Inch Barrel with Noveske KX-3

10.5 Spikes Tactical Barrel

Free Float vs Non Free float.

Points of contact with the barrel inhibit barrel whip during firing. Most people do not realize that the barrel can flex during use. By having only one point of contact that barrel can move without restriction and return to its natural state more efficiently. In the grand scheme of things, I can not tell the difference in accuracy but the physics makes sense and most of the rails I use are free float anyway.

6.8 barrel.  Note the 7.62 Flash Suppressor Compensator.

Rails

This is where the price of a weapon can really change. In the last ten years a rail system has become standard equipment. Lots of “cool guy” stuff can be added (while increasing the weight) and make the rifle more effective.

Daniel Defense (DD) has been setting the standard on rail systems. Using their own barrel nut to hold the rails into place and 6 screws to provide a solid contact point to the weapon makes this a rock solid rail system. The near $400 price point makes it a tough choice for budget minded consumers.

3 of the 6 anchor screws

Troy is newer to the market and gets good quality rails to the end user for about half the price. The never version of the rails has an improved attachment point system. In the photos you will notice two screws at the bottom that provide the tension on the propriety barrel nut. The newer version has 3 anchors that put tension on the stock barrel nut.

Troy rifle Rails

Last Generation 2 anchor screw version.

KAC
Continuously berated due to the cost and lack of quality (the top lock down screw is easily lost). The military has spent a fortune on theses rails. In my opinion this was the system that started the craze for all of the modern variants.

14.5 on the M4 carbine, perm FH