AR not cycling properly

Austan

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  • Nov 27, 2007
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    Hey guys, I was shooting an AR yesterday that I finished putting together and it wasn't cycling properly. I would cycle the first round in, shoot, and then click. The bolt was coming back enough to eject the empty but no picking up the new round. So I cycled it manually, fired another shot then click. I did this for a thirty round mag and two twenty round mags. The next mag was a another thirty rounder. The same as previous with the exception that I had it function properly for three rounds in a row twice for that magazine. That was a pleasant and encouraging change of pace. The next thirty round mag was manual cycle for the first 5 or six, then bang bang bang the rest of the way through. The next mag was back to manual cycle, the whole friggin mag except the last two rounds. Some of the aforementioned cycles, the next round would be half loaded into battery but the bolt would be on top of it instead of behind it. I think I narrowed the problem down to the buffer spring being too stiff. It is the Tubb flat spring. It has a ton of resistance when pulling the charging handle back. The rifle has a carbine buffer tube and the spring is for a rifle buffer. Does that matter? Does it need to be cut down? Will it "break in" after a while?Is this not even the issue? I'm a bolt gun guy and this noisemaker is frustrating.

    The only up side of the day was my ability to monitor my shooting habits since half my shots were dryfires. I never knew when there was a live round in the chamber. A nice learning tool if it were by design.
     

    orkan

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    Re: AR not cycling properly

    Didn't think that one out very well huh?

    Carbine length buffer tubes do not use the same buffer or buffer spring as a regular rifle length tube.

    Carbine length = use CARBINE PARTS
    Rifle length = use RIFLE PARTS

     

    Austan

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    Re: AR not cycling properly

    I didn't see that there was more than one to choose from. Everything I read said that since it was flat spring it compressed much more than a normal one. I do have a carbine buffer in it.
     

    dmg308

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    Re: AR not cycling properly

    The Tubb spring may be used in carbine or rifles it is not likely the problem.More likely your gas key is not seated and staked properly.
     

    jackinfl

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    Re: AR not cycling properly

    Check your gas key. If it wiggles torque it down and stake it. I use the MOACKS from Ned Christianson.

    You say put together. Did you assemble all the parts or just install the components in the gun?

    If you could list the components and we may be able to help.

    jack
     

    Lumpy Grits

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    Re: AR not cycling properly

    Check and make sure the bolt "key" is TIGHT, check to see if the bolt "rings" a spaced correct. Try different ammo and mag.
    What ammo are you using? Factory, mil. surplus, reloads etc.
    Respectfully,
    LG
     

    Austan

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    Re: AR not cycling properly

    The gas key does not wiggle and has been staked. I have seen some peened in more than this but it is on tight. Put together means complete assembly of the lower parts. Upper was done by someone else. BCG is brand new RRA. If it needs to be a rifle buffer tube/buffer so be it. I can use the one from the other AR.

    The ammo was PMC 55fmj.
     

    scotharr

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    Re: AR not cycling properly

    I've used a Tubbs rifle spring in a carbine successfully, not that I'd recommend it...but it worked for my LaRue upper with a Carbine buffer.
    www.davidtubb.com/tcom_images/ar15_images/cs_flatwire_brochure.pdf
    As shown in the pdf, there are separate springs for carbine and rifle systems...get the right spring (& buffer) if you are having problems.

    I'd certainly try the rifle length lower if you have one laying around. That will help you isolate the problem.

    Have you checked the gas block for leakage? It would be pretty dirty around the gas block if there was leakage.

    What barrel is on it? How old? What length gas system?
     

    Austan

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    Re: AR not cycling properly

    The barrel is a WOA SPR. Vltor low pro gas block, rifle length gas system. No leakage aroung the gas block. I did see in the PDF that there are more than one and am in contact with Mr. Tubb to purchase the carbine spring. This upper will most likely end up on a rifle length lower.
     

    Scottmilk9

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    Re: AR not cycling properly

    Austan,
    Lets figure this out by eliminating a few things.

    1st. check gas rings, if its a new bolt, it shouldn't matter, but just in case. extend the bolt out from the carrier, place it on a flat surface, if it falls(rotates) the gas rings are bad.

    2nd. Place a carbine spring in, if it works then there is your problem, if not well........go to step 3

    3rd, un bolt your gas block and tweak it a little either way to make sure you have it over the gas port. Sometimes 1/16th inch off can be a big problem.

    Let me know after those 3 things.
     

    Victor Co Heather

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    Re: AR not cycling properly

    I've had this same problem on and off. I was shooting wolf (crap ammo) with a H2 heavy buffer and heavy spring. This combo caused the exact same problems as you described. I went to a lighter spring/buffer combo and now use federal ammo and all is well.
     

    GBMaryland

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    Re: AR not cycling properly

    Lemme ask:

    Does anyone have a decent buffer and spring for an A2 stocked lower?

    I'm looking for something a little lighter than normal, as I'm finding that I get the symptoms of short-strokes with any ammo that is not HOT.

    Basically, milpec ammo works, and lighter loads do not.
     

    crossgun

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    Re: AR not cycling properly

    Am I missing something? What is so special about the Tubb's spring that it worth having over the good old mil-spec spring?

    Sometimes the original way is still the best way.
     

    tireys

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    Re: AR not cycling properly

    I am using 20" rifle length gas system with a factory buffer and spring from Rock River in a tactical car stock. Its the same lower that I used when I had a 16" Midlength gas system upper on it. I swapped the Mid length upper out for a 20" upper a couple weeks ago. Last week I finally got it to the range and was pleased with the results. The bolt cycled just fine with factory 55gr. Remington .223 rem and the same load in Hornady ammo. I am pretty sure that the middy's have the car buffer and spring in it since its a tactical carbine stock. Should I have experienced a different result?

    dscn1076.jpg

    By sambam45, shot with COOLPIX L11 at 2009-03-31
    dscn1056.jpg

    By sambam45, shot with COOLPIX L11 at 2009-03-16
     

    dmg308

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    Re: AR not cycling properly

    The stock spring is a cheap wire spring .The tubb is a chrome silica flatwire spring which is super consistent and virtually never wears out.The improvement in cycling is noticable try one you wont go back.The cost is negated by the extended service life.
     

    Scottmilk9

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    Re: AR not cycling properly

    I do know Mr. Tubb's springs are superior, but I never had a buffer spring wear out and i shoot about 12K a year. The spring is not gonna be a major cause of problems on cycling. it is a gas issue(carrier key, gas rings, gas block)
     

    Cmonroe

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    Re: AR not cycling properly

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body">I do know Mr. Tubb's springs are superior, but I never had a buffer spring wear out and i shoot about 12K a year. The spring is not gonna be a major cause of problems on cycling. it is a gas issue(carrier key, gas rings, gas block) </div></div>

    +1, look at the gas tube where it goes into the gas block, do you have carbon building up on the outside of the tube?
     

    tireys

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    Re: AR not cycling properly

    When I initially read the opening post of this thread that was what it sound like to me was a GAS issue because that is the key to the whole cycle of operations.

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Scottmilk9</div><div class="ubbcode-body">I do know Mr. Tubb's springs are superior, but I never had a buffer spring wear out and i shoot about 12K a year. The spring is not gonna be a major cause of problems on cycling. it is a gas issue(carrier key, gas rings, gas block) </div></div>
     

    tireys

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    Re: AR not cycling properly

    But, I had to read this a couple of times and it does sound to me that it is a spring issue. The rifle fires and begins extracting the spent shell as the gas is blowing back the bolt and then ejects the spent cartridge and before it finishes the cycle its sent back to battery without a new round so it is only recoiling enough to throw out the new and not pickup another round off the follower so it seems to me that your problem isn't gas but infact a super stiff buffer spring. I am not a armorer or a AR guru by no means. Just my 2 cents
     

    Scottmilk9

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    Re: AR not cycling properly

    I don't want this to be a pissing contest, by no means. But... to finish the cycle the gas has to blow back the bolt, and its not picking up the next round. The only way it can be the spring, is if you have a rifle spring in a carbine buffer tube, which means it wouldn't compress enough to allow the bolt to come back far enough.


    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: StealthMode223</div><div class="ubbcode-body">But, I had to read this a couple of times and it does sound to me that it is a spring issue. The rifle fires and begins extracting the spent shell as the gas is blowing back the bolt and then ejects the spent cartridge and before it finishes the cycle its sent back to battery without a new round so it is only recoiling enough to throw out the new and not pickup another round off the follower so it seems to me that your problem isn't gas but infact a super stiff buffer spring. I am not a armorer or a AR guru by no means. Just my 2 cents </div></div>
     

    jasonk

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    Re: AR not cycling properly

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Austan</div><div class="ubbcode-body">The rifle has a carbine buffer tube and the spring is for a rifle buffer. </div></div>

    From the OP
     

    Scottmilk9

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    Re: AR not cycling properly

    Thanks Jason, change your buffer spring to a carbine spring.

    Stealthmode, you were spot on with its a buffer spring problem.

    I should have read every bit, my mistake.
     

    Austan

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    Re: AR not cycling properly

    Well it's not figured out quite yet. I'm taking it out tomorrow to try some stuff. Mr. Tubb informed me that there is indeed only one spring offered for the AR, it is a 36 coil spring to be used in either rifle or carbine buffer tubes. He also mentioned making sure the carrier was lubed properly and this could also cause the issue. The other alternative is to cut the spring shorter a couple coils at a time and trying it that way. I won't run with this idea as this rifle will eventually sport a rifle stock. I'll also try the upper on a rifle lower with standard rifle spring to assure that it is indeed the issue. I'll report my findings tomorrow.
     

    marduk185

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    Re: AR not cycling properly

    hey, i could totally be wrong but id almost bet you got a spring missin in the trigger group causin the diconnecter to malfunction. check that before hackin buffer springs. also try out different ammo. all 556 not created equal. good luck, ar's can be finicky.
     

    scotharr

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    Re: AR not cycling properly

    Austan, you've got an upper from a top builder. Try putting a different, "known good" lower on it. If that doesn't work, contact White Oak and ship it back to them.
     

    bigwheeler

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    Re: AR not cycling properly

    Maybe I missed it but I don't see you ever stating you have a carbine buffer in your
    carbine tube after you asked. The carbine buffer is shorter as posted in the pic
    above.
     

    Austan

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    Re: AR not cycling properly

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Austan</div><div class="ubbcode-body">I didn't see that there was more than one to choose from. Everything I read said that since it was flat spring it compressed much more than a normal one. <span style="text-decoration: underline">I do have a carbine buffer in it.</span> </div></div>

    Quoting myself.LOL

    I didn't and won't get a chance to shoot it today, been on daddy duty all day. It will have to wait for Saturday.
     

    tireys

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    Re: AR not cycling properly

    That Carbine tube and buffer is mine I just posted it for GP.

    <div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bigwheeler</div><div class="ubbcode-body"> Maybe I missed it but I don't see you ever stating you have a carbine buffer in your
    carbine tube after you asked. The carbine buffer is shorter as posted in the pic
    above. </div></div>
     

    Austan

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    Re: AR not cycling properly

    Alright guys, I took both AR's out and shot today. I left the configuration alone for the start. First lubing the bolt carrier per Mr. Tubbs recommendation. Well that helped a great deal right off the bat. The first round went fine obviously since it was hand cycled. It failed to pick up the next round again, fed it about half way and stove piped it. Oh no, not this again. Hand cycled that one out of the way and bang, bang, bang, all the way trough the mag. Next mag ran perfectly. It still doesn't come all the way back and lock open after the mag empties. I switched it to the other lower and it ran perfect. I then swapped out the spring with a standard carbine spring in the carbine buffer and it ran perfect. I then put the Tubb spring in the rifle tube and it ran perfect. It is indeed the spring that was causing the issue. I think Mr. Tubb was right, if I cut the spring down, even just a couple of coils, it should work without any problems. It seems to be right on the edge of working, just a little too tight. Of, course I didn't bring anything to cut it down with. As I stated previously, this will end up with a rifle stock on it as soon as I decide which one. I'm thinking the PRS, I just want to see one up close first, unless you guys have a better recommendation. In the end, the Tubb product is very good and I'll be getting another one. It does eliminate the "twang".
     

    tireys

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    Re: AR not cycling properly

    Excellent, So instead of cutting the spring down are you going to leave it as is and just use that spring in the Rifle stock when you get it?
     

    scotharr

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    Re: AR not cycling properly

    Thanks for following up and letting us know. Nice to see problems resolved. It's also nice when the problems are simple...then again they are all simple after you solve them
    smile.gif
     

    Austan

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    Re: AR not cycling properly

    Yes, I'm going to leave it as is. I will buy another Tubb spring to see if it has the same issue. He mentioned that they sell thousands of these a year with maybe five issues. I'd say that is a pretty solid product, plus it does get rid of the "twang". I've heard people say they like, I'm not one of those people I guess. If I have to cut the next one done, that's easy enough to do.

    Yeah Scooter, it didn't seem that difficult of a problem but being only vaguely familiar with the AR platform, I figured I'd better ask first. Thanks for all your replies gentlemen.

    Austan