AR15 Preventative Maintenance/Scheduled Replacement of components

[navybowhunter]

So I figured I'd start this thread on AR15 Maintenance.  It is the most popular rifle in America, and FiremanBob has pretty much covered the 10/22.

I will speak to my competition AR's, but this is applicable to all of them.

After shooting:
I clean the chamber, with a chamber brush and Brakeclean.  Then I use a chamber mop, and dry it out.  That is all.  NO lube in the chamber unless it is going into deep storage.

The BORE I rarely clean.  I will clean the carbon fouling out every 500 rounds or so.  This is with a Nylon bore brush, and a JP Enterprises bore guide.  I will follow that up with some patches soaked in the same carbon fouling cleaner and then dry patches.

Annually, I do the JB Enterprises bore paste and final finish with the VFG felt pellets.  I am not very aggressive with it, maybe 20 passes with the bore paste, remove it with a VFG pellet soaked in Kroil and dry pellets till it is all removed.  This is to remove any built up copper fouling.  I do not remove all of the copper fouling, as some of that needs to remain to maintain accuracy.

The flashhider, gets a soak in brake clean, to remove any built up carbon.

The upper receiver gets brake cleaner, and then wiped dry.  I use Frog Lube to coat the inner receiver.

The BCG gets disassembled after each session, and ultrasonically cleaned.  I use a GG&G bolt cleaning tool to remove any remaining carbon fouling from the rear of the bolt.

BCG gets frog lubed and reassembled.

The lower receiver gets wiped down, mag well and the hammer.  I do not brake clean the lower.  The Giessele trigger is properly lubricated.  Annually, I will brake clean the lower, and then re-lube/grease the trigger per the manufacturers instructions.

The Buffer and Buffer spring, I clean those annually as well, and lubricate and reinstall.

When it is time for a new barrel.......

For me, I have opted to replace my barrel after 2000 rounds.  It will still hold the X at 600, but....is likely on its downhill trend for accuracy.  Barrel life when we are shooting the heavier bullets tends to go faster.  Typically a barrel will hold the X for 3000 ish rounds, dependent on the barrel.

Anyways, when it is time for a barrel change, I order a new barrel AND the following:

- Barrel Nut
- Gas Tube *Smart move to replace, the gas tube is designed to fail at some point, likely well within limits at 2000 rounds, BUT why risk it?  It is cheap enough, and you are removing/replacing the barrel.  Might as well replace it.
- Bolt *one can reuitilze the old bolt, if you have headspace gages, you can verify if your old bolt will still work.  Bolts are not that expensive, so I replace.  IF retaining the old bolt and the headspace has been verified to be good, recommend replacing the gas rings and the Extractor.
- Firing Pin
- Buffer Spring
- Buffer

Annually, I also check the torque on my gas block, scope mount and anything else that requires a torque.  I mark them with a witness mark, so I have a visual reference if stuff starts to loosen up.

What tools are required for a barrel change, and for all of the above?  Not too many things.

You will need:

- A bench with a sturdy vice.
- A set of Roll Pin Punches
- If using an A2 type rifle, an A2 gas tube removal alignment block (this makes fast work of the task)
- An Upper receiver vice block
- A Barrel Nut wrench that will be appropriate for your barrel nut.  (many quad rail manufacturers have manufacturer specific barrel nuts, Yankee Hill is one that comes to mind, and they ship their nuts/rails with the appropriate adapter).
- A set of picks, to remove gas rings if reusing the old bolt
- Headspace gages (GO/NO GO and a FIELD) *Note on headspace gages, if using the old bolt on barrel replacement, it may close on the NO GO.  Then move to the FIELD gage, if it doesn't close on the FIELD gage, you are good to go.**
- Some ANTI-Sieze grease (stuff that makes one look like the Tin Man) for the barrel nut threads
- Torque Wrench for the Barrel Nut *Honestly, I do not torque mine.  The range for the torque spec is very wide.  I get it as tight as I can and back off or reef on it a lil more, to get the gas tube aligned properly.
- A nice to have tool is a gas tube alignment tool.  Not a must, but very nice to have.

If you buy the Weller AR kit, it pretty much comes with all of the above.  It will not come with headspace gages.

AR15 Uppers are easier in my opinion than the lower receivers.  If you have the basic skills to assemble a lower, you can also do your own uppers.

Brownells, has some awesome YOUTUBE videos that cover the whole process.  If ever in doubt, youtube is your friend.

Lastly, if you are replacing the bolt with the barrel, no need to check the headspace.  Especially if buying a reputable barrel.

The typical "do it at home armorer" is not equipped to correct headspace on the AR.  The AR barrels come headspaced already, by virtue of the barrel extension, of which I NEVER recommend even trying to remove that.  The only thing that gets smaller, is the bolt face from the pounding it takes in live fire.  SO...a good rule of thumb is to always replace the bolt when replacing the barrel.  If you do that, headspace gages are not needed.

ENSURE that when ordering a barrel, you know what you need in reference to M4 Feed Ramps.  If your upper has M4 Feedramps, you want a barrel with M4 Feedramps.  Most barrels and uppers these days come with M4 feedramps.

Some consumables that are nice to keep on hand, for yourself, or to be a hero for a friend:
- Gas Tube
- Gas Tube roll pin
- Bolt
- Buffer
- Buffer Spring
- Gas Rings
- Extractor
Do I discard my old barrel with 2-3000 rounds on it?  NO.  I will save that and build it up on a rifle for reduced course shooting, or Appleseed AQT's or KD.  The barrel will still shoot well within 400 yards, maybe even 500. 

If one has NONE of the above tools, to perform the task, consider this.  What does your gunsmith charge?  I would think it would be at least $75 in labor in addition to the parts. 

For a little more than $75 (not counting the headspace gages) you will have paid for your tools after 2 barrel replacements.  And you will have the pride in ownership that comes from doing it yourself.  And....if you wanted to you could likely do the same for your friends and charge them beer or whatever compensation would be appropriate.  AND it is FUN!

Enough on this for now.  Thoughts?

[navybowhunter]

One more thought on this....

If you ever wanted to shoot longer bullets, like the 80 grain bullets....seating them off the lands....

Before you install the new barrel, now is the best time to get that measurement for any bullets you decide you may want to use.

Hornady makes a tool for this.  2 tools actually, they are called Overall Length Gages, and come straight (for bolt rifles or break actions) and curved/angled for semi autos.

I currently shoot the 80 Sierra Match King and the 80 Hornady AMAX. 

A wooden dowel, that is small enough to insert inside the bore is something I highly recommend as well.

Using the straight OAL gage is a lot easier than the angled/curved one you will need to use once the barrel is installed.

So, at this point, with the new barrel, simply grab any of the bullets you intend to load longer and take the measurements.  The Dowel is used in conjunction with the OAL gage, and is also helpful as you will likely get the bullet stuck in the lands several times.

Once you have your Measurement "to the lands" record that in stone, in your data book, on a grease board in reloading room, etc....wherever it will be a ready reference for you once you start to reload for that barrel.

LOT easier to do this with the barrel removed.

R/
Chris

[Mutant Texan]

Interesting read.  I have never replaced a part in any of my rifles.  I do have multiple rifles and would have the option of cannibalizing parts off of the other rifles.

As far as cleaning the trigger, I on occasion will spray brake cleaner into the lower's fire control group and scrub carbon out.  I will then put a synthetic oil in on all of the springs and work the FCG by hand to work the new oil in.

Honestly, I rarely clean more than the BCG and barrel.  I will simply pull the bolt out, clean the carbon out with a tooth brush and a solvent I run a bore snake through my barrel dry.  I have never come across lead fouling in the barrel and any copper jacket material left in the barrel will get cleaned out with the bore snake.  I have been known to spray brake cleaner down the barrel but the snake is always run dry.

I would be interested in seeing the failure rate of a gas tube.  If the tube was made from an exceptional alloy, you may never have to even worry about failure because there are steel alloys that do not suffer from metal fatigue below a certain stress level.  I imagine that a carbine gas length system will challenge the system more than a rifle length gas system.  I don't even want to even think about a pistol gas system.

I do like pulling machines apart and dissect them to figure out how they work.  Just keep in mind that there is always a risk of losing or damaging small parts (springs are the likely suspect).  There is also the risk of not getting it back together correctly and being ignorant of the error until you are on the range.  I recently built a new lower and learned the hard way that the hammer spring ends are supposed to go above the trigger pin.  If you don't put the spring ends above the trigger pin, the trigger pin will walk itself out. 

I also don't trust a gun's reliability until after it has been functionally tested with several hundred rounds.  The rifle is then dirty again after the test so I have never taken a rifle apart.  I also trust a lower with a high round count more than a new from the box rifle.

I have never changed a barrel out due to wear.  I have however built my own upper from parts and have the tools to torque the castle nut down and could perform the barrel swap if I had to.  I am not going to say that the barrel has no wear in it, but I own several rifles that have case hardened barrels.  This is why I am such a fan of CMMG.  The engineer in me recognizes a good thing when I see it.  I have run many thousands of rounds through my Mutant rifle and can't see any noticeable wear in the barrel.  The standard and SS barrels I am sure have wear but I am not sure if it will adversely affect the accuracy to a noticeable amount.

I recently built my first lower and torqued everything to spec.  I also used the blue thread locker to prevent the parts from loosening up.  I highly recommend thread locker on just about any threaded part.

The trick for reliability of a rifle is keeping the moving parts clean and coated with a very thin layer of oil and a clean barrel (meaning dry bore snake)  You can massage oil into the anodized Aluminum parts after scrubbing them down with brake cleaner.

[navybowhunter]

MutantTexan,

My comment on the gas tube failing at some point, was after watching a youtube video where a guy ran magazine after magazine thru an AR15, it is a pretty crazy video.  The muzzle device comes loose on the rifle after a certain amount of rounds, and the gas tube eventually did fail.

I only change the gas tube during a barrel change due the fact that it is something that needs to be removed anyway and is a cheap replacement, an insurance policy of sorts.

Being that the AR15/M-16 is a military style rifle, there were surely studies performed on failure rates.  I have never really researched them, but I know they exist.  MTBF (Mean Time Between Failure) is what I am alluding to here.

I also use my rifles solely for competition, so it is an added level of insurance for me to replace certain things on a recurring/scheduled basis.

I did notice the other day that the bolt release catch is wearing significantly on my primary rifle.  I have installed one of the Magpul BAD levers, so I do not have to reach over the scope to close the bolt.  I think that has added some different stress to the bolt catch.  I will keep an eye on it.

R/
Chris

R/
Chris