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You and Your AR-15

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This topic contains 18 replies, has 10 voices, and was last updated by Profile photo of Bob gunnerbob 2 years, 7 months ago.

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  • #26346
    Profile photo of DiznNC
    DiznNC
    Participant

    OK it’s time for that what should I do to maintain my AR thread again. Quite frankly, the current quality from the main brands is so good, there are many other things you should worry about first. But anyways here’s a guide.

    This is all based on your firing schedule. If you don’t even shoot 50 rd a month, don’t worry about it. If you shoot maybe 500 rds a month, then there’s things you might check. And finally, if you are shooting 1,000 rds or more a month, you need to be checking a few things.

    I have had a few talks with my SF bud about this. Like hey man have you read all those threads on line about parts wearing out and all that, so what’s your take on that? So here’s what they do. Before each deployment, which is basically an 18 month cycle, they have a complete re-build of each M-4 they own. So every gun is completely dis-assembled and re-built with practically all new parts, especially all the springs n things. The bore and chamber are mic’d. New bolt and headspace check. New ejector and extractor and springs. New recoil spring. New LPK, especially springs. Even the receiver detents and springs. Mag catch, bolt catch, yada, yah. So this would be your upper limit, if you are on a heavy firing schedule. Now these guys don’t keep a strict round count like a “long gun” but he would put somewhere around 10K rds through the pipe each deployment. So they didn’t keep a strict record of how many rounds a part went before it was worn, or anything. They just re-built everything to make sure.

    But back to us, what should we be doing. Let’s start with some service intervals. Besides just cleaning and oiling it after use, and doing your normal function or “pre-combat” checks, the first interval is at approx. 5,000 rds. Inspect bolt for cracks, especially around lugs and cam pin hole. A good MPT bolt should last 10K but needs to be checked at 5. You have the option of replacing extractor and ejectors at this point. Check firing pin protrusion. Check headspace. This should be fine. Check recoil spring length. If 1″ or shorter than new, replace. Function check LPK. Pay particular attention to trigger pull and release. These should just be getting broken in nicely at this point but make sure everything is working properly. Make sure safety is nice and smooth with positive detents. This is mostly a check at this point to make sure nothing is worn pre-maturely.

    Now the 10K check. This is where you should see some wear and tear and things need to be replaced. Do the same checks as the 5K. Bore and chamber. Bolt assembly. Headspace. Recoil spring. LPK. Mag catch, bolt catch. At 10K, I would be looking hard at the bolt. A good MPT bolt is good for at least 10K, but may break any time after that, according to anecdotal evidence. So if it was me, I’d go ahead and replace it (complete bolt assembly) at this point. Same with recoil spring. On the LPK, if everything is working well, I would go ahead and replace springs and detents.

    You can repeat these two checks every 5 and 10K up to 20K. That’s when you need to take a hard look at the bbl. I know you accuracy types are thinking I’m nuts to go out 20K on a bbl, but a good modern one can do that and hold acceptable COMBAT accuracy.

    So that’s about it on round count intervals. If I’ve missed anything, you armorer types chime in. As an alternative, you can also go on a time interval, and do an annual inspection. So it would basically be 5 or 10K check just done on an annual basis.

    To give you an example, I have two BCM uppers, built on various lowers and other parts. I have had zero problems with either piece, with about 5K round counts through each gun. I just recently went through them both and replaced all springs n things. Bolts, bores and chambers were fine. Now that is a conservative schedule (of course) which is a combination of a 5K and annual inspection, cuz that’s about what I shot last year.

    Like I said, I’m really impressed with the quality of things these days. Unless you’re really cranking out a lot of rounds you really shouldn’t have too much to worry about. I used to carry complete spare rifle, and parts kits every where I went. Nowadays, I am pretty confident of my rifles, and don’t carry much more than cleaning supplies.

    CTT 1505, NODF 1505, CP 1503, LN 1, RC II, Rifleman

    #26347
    Profile photo of Trailman
    trailman
    Participant

    So,
    I’ve never built one and other than Youtube videos never had training on building one or mic’ing the chamber etc etc. My next rifle will probably be an 80% lower build considering my location. What recommendations you have for me Obiwan? I’d take a class over a video or a manual in third place since I’m a hands on, picture kind of guy. (I smell 1Sgt training)

    I keep a spare armorers part kit on hand and two complete BCG’s I bought from PSA as spares and/or towards a rifle build. That’s about it for now.

    Edit: My point is whats the best way to gain the knowledge and skills to perform what you are saying and minimizing the risk of blowing my head off in the process.

    CRM, CTT 1501, CP11/15, CTT5/16, FoF, DCH, CLC Opfor, Team Minion

    Just remember, Anne Frank was a criminal because the government made her one and she died because she broke the law.

    #26348
    Profile photo of DiznNC
    DiznNC
    Participant

    Find a good machinist for help on the 80% build. Lots of things to screw up if you haven’t done any machining. Not calling you a maroon, just trying to help you stay out of trouble! Once you have one under your belt, then it should be smooth sailing. Just like any first article in manufacturing; you don’t know about 10 different things until they pop up.

    The mil-spec manuals are actually a good starting place, especially for function checks, periodic maint, that kind if thing. I just learned by doing everything wrong first; you could probably go to a good armorer’s course instead.

    And yeah, we’ll try and do some more posts on this stuff.

    CTT 1505, NODF 1505, CP 1503, LN 1, RC II, Rifleman

    #26352
    Profile photo of Mike Q
    Mike Q
    Participant

    I built mine using an 80% lower and it has worked really well. Mine is essentially a BCM rifle with an 80% lower. The lower parts kit was DPMS standard.

    I think the worst thing people do when building the rifle is adjusting the barrel length with wrong sized gas systems. I went with a full 16″ barrel and a mid-length gas system. Not a 14.5″ barrel with a welded flash hider, actual 16″ barrel. I also used a standard spring and buffer.

    Simple and easy. When you start looking at all the after market buffer springs, buffers, and triggers you can get yourself into trouble. You can have cycling issues, ejection issues, etc, if you pair them incorrectly.

    In regards to the 80% lowers, if you want to do it yourself, then spend the money and get a jig to help you.

    There never seems to be enough time to do it right, but there is always enough time to do it twice.

    CRM Sept. 2014, CTT 1505, CTT July 2015, RC-Rifleman 1502, CP Nov. 2015, FoF March 2016, CCW May 2016, FoF Oct. 2016, FoF Nov. 2016, CLC April 2017, FoF Nov. 2017, Alumni weekend Aug. 2018, CQB Dec. 2018

    #26361
    Profile photo of DiznNC
    DiznNC
    Participant

    There’s a lot of truth in that post. Tooling is everything. With the right tools you can move heaven and earth. Drilling jigs, properly installed, as in rock steady, can make or break you. Drill bits will deflect if not supported properly with bushings. They can also wander or oblong slightly. Using pilot bits to center everything and then drilling up to size- golden. Using a drill lube, using the right RPM and pressure for the material in use. Basic machine shop stuff, but will bite you in the ass if not done properly. It doesn’t take much to be out of spec, just by a few thousandths. But it will be enough to affect the reliability of your build.

    And parts combinations. Bbl length and gas port dia. Buffer weight, and extractor spring pressure. On and on. This is why the design gets a bad name. Lots of rifles get thrown together and guys not wanting to admit they didn’t do it right. So Stoner takes the heat.

    CTT 1505, NODF 1505, CP 1503, LN 1, RC II, Rifleman

    #26379
    Profile photo of JeffSags
    JeffSags
    Participant

    Universal 80% AR-15 Easy Jig

    Easy-peazy :good:

    CRCD AUG 13, CRCD MAR 14, CP AUG 14, CR MAR 15, Shivworks ECQC, MVT RIFLEMAN, CTT AUG 16, CQBC

    #26380
    Profile photo of Jake
    Weber
    Participant

    Good post Diz and thanks for the info. Make this a sticky.

    My mom said I could be anything I wanted to be when I grew up. So I chose to be a man.

    #26381
    Profile photo of Trailman
    trailman
    Participant

    Universal 80% AR-15 Easy Jig

    Easy-peazy :good:

    Erik passed on that information to me a while back and hen the times right I think that’s where I’m going to tools and parts. :good:

    CRM, CTT 1501, CP11/15, CTT5/16, FoF, DCH, CLC Opfor, Team Minion

    Just remember, Anne Frank was a criminal because the government made her one and she died because she broke the law.

    #26390
    Profile photo of First Sergeant
    First Sergeant
    Moderator

    One thing on the 80% lowers. Make sure the mag well is to spec. At the CRS class there was an 80% lower build. The gun ran fine, except it wouldn’t run Pmags and one other type of mag. It ran Lancers and GI mags fine.

    Something to think about.

    FILO
    Signal out, can you identify.
    Je ne regrette rien...
    Klagt Nicht, Kämpft

    #26410
    Profile photo of DiznNC
    DiznNC
    Participant

    One thing I learned in gunsmithing skool: if you are going to play around with this stuff, get a good, in-spec example of something to compare things to. That way you always have a reference to what’s right. Like a 3-D blueprint. Mic everything and compare.

    If you relieve your magwell, do not remove any material on the BACK wall. Take off from front or sides. The back is very thin to the passage for the bolt catch/release.

    Also mags can be sensitive to mag catch pressure. Try backing off a turn and see if that helps. Sounds too simple to work, but it does.

    CTT 1505, NODF 1505, CP 1503, LN 1, RC II, Rifleman

    #26416
    Profile photo of Free Chicken Dinner
    RRS
    Participant

    My Zimbabwe .02 your weapon is not a range toy. I spent high dollar on a LMT with doodad high end stuff when a Colt would be more than enough and probably a better choice than most.

    More zinc pennies, if I were to up it to a 7.62 then I might want the high dollar models like LMT or Knight, DD and such.

    Tactical training for Liberty, Fraternity, Excellence

    #26426
    Profile photo of Trailman
    trailman
    Participant

    My Zimbabwe .02 your weapon is not a range toy. I spent high dollar on a LMT with doodad high end stuff when a Colt would be more than enough and probably a better choice than most.

    More zinc pennies, if I were to up it to a 7.62 then I might want the high dollar models like LMT or Knight, DD and such.

    My reality I’m working through here is that I’m in Maryland and have certain legal loopholes to squeeze through. That’s one of the reasons I’m looking at the know how to do an 80% build. Not to mention that if I go anywhere in public with a post ban rifle it has to be an HBAR profile not to garner attention. Currently I’m looking to put at least four more into the inventory for up and coming folks.

    CRM, CTT 1501, CP11/15, CTT5/16, FoF, DCH, CLC Opfor, Team Minion

    Just remember, Anne Frank was a criminal because the government made her one and she died because she broke the law.

    #26427
    Profile photo of Free Chicken Dinner
    RRS
    Participant

    I hear you, not specifically addressed to you and your situation. I don’t think I would feel that out of place with the HBAR save a decent optic, which I need.

    Tactical training for Liberty, Fraternity, Excellence

    #26430
    Profile photo of DiznNC
    DiznNC
    Participant

    It’s all good. I keep forgetting about all you guys n gals in occupied territory. If’n it was me, yeah I’d doing exactly what you’re doing.

    When I wuz n Kali, I had guns that spent more time in PVC tubes than in open sight.

    CTT 1505, NODF 1505, CP 1503, LN 1, RC II, Rifleman

    #26447
    Profile photo of Thomas
    Thomas
    Participant

    We need a lesson in PVC tube activities. The times they are a changin’.

    #26453
    Profile photo of DiznNC
    DiznNC
    Participant

    Yeah

    CTT 1505, NODF 1505, CP 1503, LN 1, RC II, Rifleman

    #26457
    Profile photo of Max Velocity
    Max
    Keymaster

    Note: This is not Max’s response/content. Just a glitch from the transition to subscription.

    I have completed one of the 80% arms with EZ jig using a drill and router. It came out ok as I am no machinist but seems to be pretty functional. My best guess is the the lower parts kit is going to see faster wear vs a factory finished lower.
    I used the tool kit that they offer on their website but I would suggest using a different drill stop collar for the 3/8″ bit. The one they sell has a single set screw and will cant to the side giving you incorrect depths. There are much better stop collars on the web that tighten around the bit evenly.
    Additionally, you need a compact base/ palm router like the Bosch Colt to route the trigger pocket. A large router will not work. You may want to have extra 3/8″ bits on hand because you do most of the work with them.

    Also, I use a Sig M400 as my main platform and its pretty excellent. There are some extra features like abmi mag release, ambi QD and a lower spring detent that keeps the lower and upper in tension and therefore not rattling. Pricing is around the Colt.

    #27575
    Profile photo of Free Chicken Dinner
    RRS
    Participant

    ARs are both a hobby and a tool, the experts here have rightly separated their uses. Go to ARcom or whatever it is and its hobby folks tinkering, come here and its people who use them as a tool.

    I appreciate the work being done here to cut thru the fog of the gun sellers that are numerous beyond count.

    Tactical training for Liberty, Fraternity, Excellence

    #27743
    Profile photo of Bob
    gunnerbob
    Participant

    Great post, Diz, and thank you.

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