Archive for the 'AR-15s' Category

Cheaper than Dirt.

If it’s not USGI-pattern (that has 20 “scallops” around its circumference), most provide a head to match their nut. But I’ve seen a few I just had to wing it with, which often meant resorting to a large adjustable wrench to fit the wrench flats on the nut.

To fit the drive, ask for a “crows-foot” attachment at an auto parts store.

If your barrel nut is USGI-pattern, get a wrench head that fits over and into as much of the nut circumference as you can. My favorites give 360-degree contact, but most are half that (or less). And make sure the doggone thing is securely fitting into those scallops!

I hold in against the wrench head when I work the wrench handle to keep the head from slipping.

Longer wrench handles are better than shorter ones. Longer makes it easier to make those often-necessary small-but-high-effort nudges easier to feel, and to initiate. I use both a torque wrench and a breaker bar, and the latter is because of the next important item.

Anti-seize! This auto-parts store item is a critical component.  It’s a copper-based lubricant intended exactly for what we’re doing here—it prevents galling.

Galling is abrasive wear from the friction that occurs when metals that are compressed against one another are put into motion.

If the compressive forces are high enough between the surfaces (and they sure can be), the friction can create heat sufficient to weld the materials together and that then removes material from one surface and places it onto the other. Not good!

To get the operation going, clean off all associated surfaces (inside of the upper and outside of the barrel extension). Slip the barrel extension into the upper (there’s a pin on the extension and a notch in the upper that line up).

Put an even coat of anti-seize around the circumference of the upper threads (I use a flat artist’s brush) and thread on the barrel nut. Using something other than a torque wrench, tighten the nut down firmly—give it a good pull—and back it off.

Repeat that three or four more times: tighten it to snug-plus and back it off.

Why?

Because that helps mate the surfaces by facing down any small imperfections (which will usually be on the upper). The anti-seize allows this tactic.

The tighten/loosen procedure is compressing tiny bits of metal, and the lube is preventing galling, as well as make it easier to loosen.

Now for more about that “alignment with the gas tube receptacle in the upper receiver. ” That is absolutely critical, or it is if you want your AR-15 to shoot as well as it can.

With a USGI-pattern nut, that means one of the scallops has to be dead center in the gas tube receptacle in the upper so the gas tube isn’t touching the nut—not even a little bit. With another style barrel nut, it might not mean a thing.

The point is that if there is an opening on the nut that should align with the gas tube receptacle, it has to align!

That is now when and how the gas tube alignment tool really helps. Remove the bolt from the bolt carrier group, insert the tool in the carrier key, and slip it into the upper. There should be a gap 360-degrees around the tube. It’s a tiny gap, but it’s a gap.

Ultimately, final check it with the gas tube itself, and the test then is that the gas tube should rattle—move freely all directions.

This isn’t an evolution I’ve performed.  I’d like to think I could watch before doing it.

What was that you said, controller?  I didn’t hear you.  Speak more plainly.

Except the last part, this is a good history lesson.

“At a distance of approximately 15 meters, one Ranger fired an AR-15 full automatic hitting one VC [Viet Cong guerrilla] with three rounds with the first burst,” one report read. “One round in the head — took it completely off. Another in the right arm — took it completely off, too. One round hit him in the right side, causing a hole about five inches in diameter.”

Another run-in detailed five kills with AR-15 rifles — “back wound, which caused the thoracic cavity to explode; stomach wound, which caused the abdominal cavity to explode; buttock wound, which destroyed all tissue of both buttocks; chest wound from right to left, destroyed the thoracic cavity; heel wound, the projectile entered the bottom of the right foot causing the leg to split from the foot to the hip.”

And then the author goes off the rails.  “This history is fundamental to debates over gun reform. The AR-15 and its cartridge were designed together to create a rifle optimized to kill humans, but the rifle and ammunition have since become a mainstay of civilian hobby shooters.  This isn’t a new revelation. Eugene Stoner knew exactly what the gun was supposed to do when he designed it 62 years ago.”

As if we don’t have a right to own whatever the military owns!  I think the constitution says something about that, yes?

5010 rounds so far.  No cleaning.

I have never replaced a barrel myself, but one day I might, and if you have, he gives some useful tips.

Here’s what you’ll need: upper receiver fixture; barrel nut wrench head; 1/2-inch drive torque wrench; 1/2-inch drive breaker bar; anti-seize; gas-tube alignment tool. And, of course, a sturdy vise.

To secure the upper receiver I prefer a “pins”-style block, because it gives easy and clear access to the upper interior to make gas tube alignment checks easier. On these, the receiver lugs nestle into the block and 1/4-inch pins, just like the takedown and pivot pins on the gun itself, fix the receiver in place.

The wrench head can be variable. If you’re working with a GI-standard-style barrel nut (has the spiny scallops all around it), there are many to choose from. I prefer one that engages full-circle; most are half-circle. The more scallops engaged, the more secure the connection is under pressure. Otherwise, the head depends on the particular barrel nut that shipped with the handguard rail you chose. If it’s proprietary, most will provide a wrench head along with the package.

Torque wrench: bigger the better, I say. More leverage is easier to operate. Speaking of leverage, adding the extra length of a wrench head requires an offset adjustment. Torque wrenches are accurate and calibrated at a point halfway up the handle (there’s a mark there) to the center of the drive socket. Measure from the center of the handle to the center of the drive socket. Measure then from the center of the drive socket to the center of the wrench attachment. Add those together.

Now divide that total length figure by the length of the handle to drive center. Multiply that by the torque level you want to apply. The answer is then where to set the torque index. For instance, if you have a 15-inch long wrench, center of handle to center of drive, and attach a wrench head that extends 2 more inches beyond the drive socket center, and you’re looking for that standard 35 foot-pounds — 15 + 2 = 17. 15 divided by 17 = 0.882. 0.882 x 35 foot-pounds = 30.87. So, dial the wrench handle to “31.”

He said that backwards (divide the length of the handle to drive center by the total to get the ratio, not the other way around), although his example calculation is fine.  Make sure to read carefully and think it through.

About the gas-tube alignment tool: this can be either ready-made or homemade. I use one that’s a solid steel rod 0.180-inch diameter. If you make one from an old gas tube, for a more precise fit take a section from the gas tube body, not the portion that fits into the carrier key, and make it 3-4 inches long. This is an important tool to have.

The anti-seize comes from an auto parts store and is a copper-based lubricant that does what it suggests it does: it prevents galling. It also protects against dissimilar metals corrosion, and that includes aluminum against steel. It makes the barrel nut easier to install and then uninstall.

Get the upper fixed into whichever fixture you choose. Get your barrel. Wipe down the soon-to-be-mated surfaces to remove any residue or debris. There’s a pin on the barrel extension that fits into a corresponding slot on the threads surrounding the barrel extension receptacle in the upper. Seat the barrel into this receptacle. It usually will slip back and seat fully. If it doesn’t, don’t worry, because the barrel nut will seat it.

Next, get the anti-seize. Put a thin, even coat on the receiver threads. A flat artist’s brush works dandy.

Now get a barrel nut. I use one that I keep separate just for this next job. It’s a USGI-pattern nut that fits snugly and securely into my wrench attachment. The reason I have one that’s separate is because I sometimes “save” the supplied handguard nut until final install (I encounter proprietary aluminum wrench heads that get loose with use, as well as others that aren’t super-solid in engagement with the nut).

Fix the wrench head onto a breaker bar. Why? A torque wrench should not be used to loosen. Run the barrel nut on and tighten it firmly. Give it a yank. Then back it off, and snug it down again, firmly again. After experience you get a calibrated forearm, and you’ll get a feel for how much equals what. I take it to at least the 35 foot-pounds I’ll end up with on final install, but I’m not using a torque wrench for this step. You will, by the way, feel the effects and wisdom of anti-seize in this process. Do that a couple more times. This has seated the surfaces. It’s a sort of “truing,” but it’s really more of a mating. It’s facing down slight surface imperfections on the receiver, mostly.

Now, get your torque wrench and install the wrench head. Tighten the barrel nut until the wrench clicks. Only do this once. Don’t continue to repeat the clicks (you’re adding additional torque when you do).

Now. Here’s the trick: The gas tube has to be dead-centered in whatever it passes through. That might be one of the scallops on the barrel nut or a passage in the barrel nut, and, ultimately, the passage through the upper receiver. On some systems, there’s no association between gas tube and barrel nut. Those are bliss.

I’ve never seen a good torque wrench that would “add” torque if you repeat the clicks.

At any rate, feel free to weigh in with your own experience if you’ve done this before.

I had never seen this and Kyle does a good job of showing how to do it, but I’d want to practice it if I ever thought I was going to need it.

News from Florida.

SUMMERFIELD – Marion County sheriff’s officials say a homeowner armed with an AR-15 shot and killed two intruders and was injured himself during a home invasion robbery in Summerfield Wednesday night.

Two other robbery suspects  Robert John Hamilton, 19, of Ocala, and Seth Adam Rodriguez, 22, of Belleview  were detained near the scene, according to the Marion County Sheriff’s Office.

Nigel Doyle, 22, of Summerfield, and Keith Jackson Jr., 21, Ocala, were killed. The homeowner, whose name was not released by the Sheriff’s Office, was in stable condition at a hospital Thursday afternoon.

Rodriguez was arrested on charges of murder and home invasion robbery with a firearm. Hamilton faces home invasion robbery with a firearm. Both men were being held in the Marion County Jail without bond.

Deputies got the call at 8:21 p.m. Wednesday and went to the home at 14999 SE 32nd Court Road in response to a report of shots fired.

Sgt. Micah Moore found Doyle with a gunshot wound and a shotgun next to him on the ground. Deputies entered the home and found Jackson dead on the dining room floor. Detectives said he was wearing a “Jason” mask on top of his head, gloves on both hands, jeans and a black shirt.

They all look so nice, don’t they?

So you can tally yet another multi-intruder home invasion where an AR-15 and [presumably] standard capacity magazine saved a life.

Mr. Stephen Bayezes says hello.

John Lovell gives a tutorial.  I still consider the Magpul “Art of the Tactical Carbine” to be the best.  However, John provides some helpful tips.

Finding the “small of he shoulder” is difficult if you lift weights.  What happens is that the butt always lands on the pec.

Also, the thumb-over-bore grip is cool, but my son said what John did.  My son conducted room clearing for hours and days, and the only grip that works for that long is a much closer one.