Posted on 03/06/2020 7:27:03 AM PST by Black_Rifle_Gunsmith
How to Install The AR-15 Barrel and Gas System
Building an AR-15 upper piece by piece? Upgrading your barrel? Maybe you're swapping 5.56 or .223 for 300 Blackout like we are today. This guide illustrates how to install the AR-15 barrel and gas system. Virtually all AR-15 barrels ship with the extension already threaded and torqued. The headspace must be perfect, the index pin must align with the gas port perfectly, and torque requirements are high, usually well over 100 ft-lbs. We don't recommend trying to install the extension onto the barrel yourself. We're putting together a 300 Blackout pistol upper for this install, but the installation steps and torque specs are the exact same if you're building a regular AR-15 rifle or pistol with a 5.56/.223 barrel. Total time required is approximately 30 minutes to one hour, and some basic tools are required or recommended.
This guide covers:
A tip that might help, I replaced my forend and had to use Map gas torch to break lose the barrel nut, just a thought.
It's not that it's so terribly hard to build an upper, but it requires specialized tools, torque wrenches, and clamping fixtures that I would have spent almost as much in tooling to build an upper as I would just buying a completed upper.
If I were into swapping handguards, gas blocks, barrels, or building multiple ARs, the investment into the specialized tooling is justified.
For my single AR, a stripped Poverty Pony lower, and a completed upper with a lower parts kit from PSA was the extent of my commitment to building an AR.
Going by the old adage that "two is one, and one is none," if the government ever asks, the number of ARs I own are 'none.'
If it can’t be fixed with a cold chisel, vice grips and a hammer, I should not be working on it.
Bump (not stock).
All of my builds included doing the upper. It's the place where your choices in components can affect accuracy. The article does not mention lapping the upper receiver. Another tool, but one cannot have too many tools.
We don’t recommend trying to install the extension onto the barrel yourself.
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Then what is the point of a how-to video?
Then what is the point of a how-to video?
Not that I have a whole lot of experience, but I've never seen an AR barrel for sale that didn't already have the barrel extension attached.
I didn't know you could buy AR barrels without extensions, unless you're a manufacturer buying barrel blanks.
Bookmark:
I have thought about doing this, albeit I have 5-6 non-firearm projects to
preform before attempting to go to blackout.
PS: Don’t I need to fill out a ATF form before I do this?
Ouch!
.
I’ll stick with
Grandpa’s ScatterGun.
No, you do not need to fill out an ATF form to build an upper receiver. However, you need to check your state laws to see if you live in a free state, or a are in a commie state like New York, New Jersey, Kalifornia, etc., to see if they allow these scary black rifles at all.
The only item that you need to fill out an ATF form on is the stripped lower receiver, which was the subject of a previous post.
I am a 26 year veteran of both the US Army, 5 years active duty, and 21 years in the National Guard. I was a Mech infantry squad leader, and a tank commander with 2 different units in Vietnam, and I was activated for Gulf War I and Operation Iraqi Freedom.
I have built from the ground up 5 different AR-15’s in different calibers, 22 LR, .5.56 NATO .300 Blackout, and .458 SOCOM.
My experience with the M-16/AR-15 and variants does not comport with your opinion. The M-16A1 was extremely reliable and even better than the AK series in mud, owing to it being largely enclosed from that with a magazine in place and the dust cover closed. We carried basic loads of 600 rounds and more and would go through most of it during firefights. As long as you were not trying to use it as a bullet hose, and burning out the barrel in full auto, (It was never intended to replace the squad automatic weapon. Full auto was for initial fire superiority and final assault only) it was quite reliable assuming basic maintenance.
Accuracy for a properly zeroed M-16/AR-15 with a barrel twist rate of 1:12 with 55 grain M-193 ammo is excellent within 300-400 yards, which is within it’s design envelope.
Later M16’s utilize heavier bullets of up to 78 grains with a 1:7 twist rate and are even more accurate at longer ranges. All in all it is one of the most versatile and ergonomically well designed battle rifles ever made.
It sure save MY life!!!
I thank you for your service!
Mine was very modest and though I was often in theater I was never a combat soldier.
Your opinion is more valuable than mine.
At the same time I can see that you are and expert on this rifle; I shirk to think of the thousands of men who, despite their training, could never quite wrap their heads around the many idiosyncrasies.
I trained on a variant of this Armalite rifle as well as on other, I maintain superior rifles, and often wondered whether, instead of teaching so many Vietnam soldiers how to incessantly clean, field strip, etc. their M-16s, we had simply given them bolt action rifles and taught them how to shoot.
It is my opinion that the rifle itself is unnecessarily complicated and, in fact, silly.
You are one who seems to master things. You mastered this rifle. Many didn’t!
“we had simply given them bolt action rifles and taught them how to shoot.”
Ask Custer how that type of slow fire went for him.
bkmk
Even though your reply is reasoned, I cannot agree with bolt action rifles as being superior for most Vietnam era soldiers. The Germans had the finest bolt action rifle in the world with the Mauser 98k, but even they realized the validity of the assault rifle concept when faced with hordes of PPSH 41 sub machine gun wielding Soviets. So they gave the world the STG 43/44 Sturmgewehr.
If you actually examine the mechanism of the AR type rifles, it is simplicity itself. The direct impingement gas system actually has few parts, because the bolt carrier also serves as a gas piston to lock and unlock the bolt, in conjunction with the cam pin. Gas is conveyed to the bolt carrier via a simple aluminium tube.
The fire control group too has very few parts, because the trigger also serves a sear purpose, and the only other major parts are the disconnector, the hammer and selector lever, and with the exception of the automatic sear and it’s spring, are fairly common to all military type rifles. The upper and lower receiver only serve to align all of the parts in proper orientation because all of the pressures and stresses of firing are contained by the bolt, barrel and barrel extension, which is why the rifle can be made so light using mainly simple aluminum forgings.
Add to that the ease of control with the straight line buffered recoil design, (particularly in full auto) and the inherent accuracy of the high velocity flat trajectory bullet, and you have a superior design. That is why it has remained in service essentially unchanged mechanically for over 55 years.
I will concede one thing, that the superb AK series works better without any maintenance at all. But if you add up the pluses and minuses of both rifles, give me Mr. Stoner’s design every day over Mr. Kalashnikov’s.
The British Lee-Enfield was a superior combat weapon; the 98 Mauser a better hunting or target rifle...
;>)
I was referring to the strength of the action and it’s design.
I agree with your assessment regarding which is the better battle rifle. I would tale the SMLE Mark III or Mark IV as my first choice every time.
In retrospect, it would have been a better long-term choice, for the US to have picked an American design (by James Paris Lee), rather than the Danish Krag...
;^)
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