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BCM upper... Issues or is this typical?

Discussion in 'Rifle Country' started by SMITHWESS, Jun 11, 2011.

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  1. SMITHWESS

    SMITHWESS Member

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    I'm new to the AR system, first of all.

    I put together a rifle recently, with the largest component being a complete BCM EAG upper half. It's a 14.5 mid with pinned brake. This one: http://www.bravocompanyusa.com/BCM-EAG-14-5-BFH-Mid-Length-Upper-Receiver-LaRue-p/bcm-uh-eag1.htm

    I've found two things that it absolutely chokes on -

    1 - Steel cased rounds. Absolutely won't feed 'em. Look, I know this is cheap crap from mother russia but I'm curious why my friends' less expensive rifles chew through it with no issues.

    2 - I recently bought a .22 conversion for it, and it gets pretty dirty shooting with the CMMG .22 bolt installed. So after firing approximately 200 rounds of CCI with the conversion I threw the 5.56 bolt back in and it would fail to eject. It looked like the bolt wasn't coming back far enough to shuck a new round off the mag, and it left the spent brass in the pipe.

    So I pulled the 5.56 bolt back out, wiped everything down as best I could with a rag, relubed the bolt and that didn't help the issue.

    After I got it home and could do a thorough cleaning the problem was solved.

    So, being new to the platform I suppose I'm just wondering if I have a very tight BCG or if this is at all common with these rifles.

    Any help or suggestions is appreciated.

    I asked BCM about it and they just said garbage in garbage out. I get that but again, why don't my friends' Stag or DPMS have the same issues?

    BTW I typically buy Rem UMC, PMC, or an occasional box of IMI. When the rifle is sparkling clean it shoots great.
     
  2. mc223

    mc223 Member

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    :p Wow that just tears me up that one of them chart toppers choked on 22 LR.:evil:






    The gas port is probably plugged with lead from the 22.:eek:

    And why would you even try to feed such a high quality rifle crappy steel cased ammo:banghead:




    o
     
  3. Z-Michigan

    Z-Michigan Member

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    1) Steel cased ammo: generally you should expect a BCM to feed this as well as any other rifle does. However, there are two possible issues. First, your 14.5" with midlength gas is set up to be really soft shooting on full power ammo, and some Russian steel-cased ammo is quite weak. I wouldn't be surprised if your feeding problem is actually a slow cycling problem from weak ammo. What spring and buffer are you using? A carbine buffer (3oz) and standard spring might fix this if you're using something heavier, along with points 3 and 4 below.

    2) All of the .22 conversion kits are kinda dodgy and will get things dirty in weird ways. I would assume this is a conversion kit issue, not an upper issue.

    3) I've found that the higher end uppers and carriers for some reason tend to be especially tight when new, and you may find things improve just from getting the gun broken in. I would try a couple 100 rounds of hotter brass cased ammo, then clean and lube really well and try the steel cased ammo again, along with a carbine buffer if you've normally been using something heavier.

    4) In general a BCM or other high end upper is going to have the gas port sized for use with hot military spec ammo (M193, M855, etc.) while the less expensive commercial guns often have larger gas ports for reliable function with weak ammo, assuming that the buyers won't use 5.56 NATO loads much if at all. I don't know the gas port size for yours, but again the 14.5" midlength is intended to be really soft shooting, and it's possible you will just need at least moderately warm ammo. The real test is whether the gun will run when it's very dirty but using M193 or M855. If it will reliably run those ammo types after 500-1000 rounds (or more) with no cleaning, but adequate lube, then the upper is functioning properly for its intended purpose.
     
  4. SMITHWESS

    SMITHWESS Member

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    It's funn you mention the gas tube because while cleaning my rifle I always look at the tube and think to myself, "How the hell do you clean THAT thing?!"

    So, how do you make sure the gas tube isn't getting clogged up? Or better put, how do you clean it when it does get dirty?

    The rifle is definitely still green. I have around 500 real rounds through it to date, and maybe the same amount of .22.
     
  5. Ramone

    Ramone Member

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    That's an interesting rig you have there.

    I can see a few reasons you might be having issues.

    1] God is punishing you for feeding crap ammo into your nice new rifle. that's a sin, son.

    2] short barrel + Mid length system is likely to be fussy about charge weight- it just might not be getting eoung gas.

    3] whacha got for buffer and springs? It might be short stroking.

    4] is the gas tube making the gas key cleanly? that is, is it lined up right?
     
  6. Z-Michigan

    Z-Michigan Member

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    The gas tube doesn't normally get cleaned, and they almost never get plugged up. Any problems with them and you replace them for about $12. But they seem to go the life of the barrel in most cases, with no issues.

    With a .22 conversion I can't guarantee anything, but I doubt it would plug up the gas system in any way that a single round of .223 wouldn't clear up.

    500 rounds of 223/556 should have the rifle reasonably broken in. Look at the buffer weight.
     
  7. TonyAngel

    TonyAngel Member

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    Bravo Company hasn't been shy about telling people that their 14.5" mid length setup runs most reliably on "full power" ammo. What this means to me is that yours may or may not run on ammo that operates at pressures less than that of 5.56 spec.

    That UMC and PMC that you mentioned is not 5.56 spec. It's .223. Of course, in my experience, the BCM 14.5" middie runs fine on the .223 stuff, but can and will choke on the really weak stuff. If you want to run cheap ammo, try the Bear ammo. It's hotter than most of the other Russian ammo that you'll find on the market.

    As was mentioned above, you can also try advancing the timing a bit by running a lighter buffer.

    Just FYI, I'd avoid those heavier recoil springs too. Just stick with milspec. There's no reason to go heavier.
     
  8. SMITHWESS

    SMITHWESS Member

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    Thanks for the replies guys.

    Somehow I knew I'd get blasted for feeding cheap crap in a nice rifle ;)
    I have never bought the steel cased ammo, the rounds I had trouble with were handed to me at the range because I wanted to experiment a little bit and didn't believe doing so would damage anything.

    I think you're on to something about the buffer/spring weights and cartridge loads. To be honest I have no idea what weight my spring is, or what weight the buffer is. Mine is unmarked.

    Here is my understanding of the gas system: As soon as the bullet passes the gas block, a portion of the gas pressure still behind the bullet is directed into the tube and back to the bolt.

    Is that correct? Or does gas begin entering the tube even before the bullet passes the block?

    If I'm correct on the first version, then a shorter barrel with a midlength gas isn't going to generate nearly as much pressure within the tube as a carbine gas on a 16" would have. Right?
     
  9. Z-Michigan

    Z-Michigan Member

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    Unmarked buffer is normally a 3.0 oz carbine buffer, which is probably the best choice for your setup.

    Yes.

    Basically correct, although gas port size also matters. The link below should answer ALL your questions:

    http://www.ar15barrels.com/prod/operation.shtml
     
  10. Z-Michigan

    Z-Michigan Member

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    FWIW, at competitions I regularly see people shooting Wolf and Tula steelcased ammo in quality carbines like BCM, Colt, etc. I don't think you should feel guilty about it at all. It won't deliver best accuracy, but for short-range carbine type uses it's probably good enough.

    Just be aware that you may need to clean the chamber thoroughly after shooting steel cased, before shooting brass cased, because the less flexible steel cases tend to cause more gunk to accumulate in the chamber, which the more flexible brass cases can then potentially get stuck in. YMMV.
     
  11. Carter

    Carter Member

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    The only thing my buddy and I run through our BCM's is brown bear, silver bear, and wolf. They may occasionally get brassed cased, but hardly ever. People who mock others for doing so really are misinformed.

    That said, I don't think a midlength system on a 14.5 inch barrel is the best setup for russian ammo. I've also heard the same for 20in upper, but the vast majority of cases I've read were the 14.5 midlengths.

    Either play with the springs or buy better ammo.
     
  12. ugaarguy

    ugaarguy Moderator Staff Member

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    I'll search for the thread, but someone here seriously hurt an AR upper doing that.
     
  13. briansmithwins

    briansmithwins Member

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    When you say 'doesn't load' do you mean the bolt doesn't travel back far enough to pick up the next round or the next round isn't fed into the chamber correctly? On the last round of a mag does the bolt lock open when shooting steel case?

    Two different problems with two different causes.

    BSW
     
  14. Apocalypse-Now

    Apocalypse-Now Member

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    wow, that's just poor cust serv right there. :eek:

    yes, that is crappy ammo, but it should feed it.
     
  15. mastiffhound

    mastiffhound Member

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    After the thread I just got done reading, this puzzles me. So much hate directed towards bushy and dpms. Mostly for being unreliable, jam-o-matic, break down prone, overly expensive, dirt. I will admit I didn't get a dpms because the barrel wasn't chromed. I have a bushy. Unknown to me my buddy just purchased a bushy too. We both went out the first time with mother ruskie ammo and no problems.

    Sorry to hear about your trouble though. Still the fact that the great mil-spec rifles can have problems too just means that no company is perfect. Thank you for posting and not keeping the problems to yourself. You can be sure that if I have a problem with the bushy I will let people know. So fast that the snakes head will spin. Hope you can fix your problem and good luck.
     
  16. ugaarguy

    ugaarguy Moderator Staff Member

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    The BCM EAG upper is a somewhat unique case. The carbine length gas system was developed for 14.5" bbl. carbines & M4s. Because many civilians didn't want the trouble of a pinned and welded flash hider or muzzle brake on a 14.5" bbl to meet minimum bbl. length requirements for a rifle, 16" bbls. became very common on civilian carbines. Because of the extra bbl. length in front of the gas port on 16" bbl. carbines the pressures are higher, the rifles shoot harder, and they sometimes need a heavier buffer to operate reliably.

    The solution several companies came up with (I don't know who was first) was the mid length gas system. This places the gas port the same distance from the muzzle on a 16" bbl as the gas port is on a 14.5" bbl with carbine length gas system, and basically equalizes the pressure.

    Running a mid length gas system on a 14.5" bbl is going to result in lower pressure - period. BCM has apparently made no secret about this, and recommends using full pressure 5.56 NATO ammo (yes, it's hotter than SAAMI spec .223 Rem.) to keep the pressure up. The primary purpose of the EAG upper is to have a very soft shooting carbine even when running full pressure 5.56 NATO ammo.

    This isn't a failure of the mil spec mfr. (BCM in this case). It's just using less than ideal ammo in a pretty specialized upper.
     
  17. Apocalypse-Now

    Apocalypse-Now Member

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    ^^good info for us AR noob's.

    during a SHTF scenario, i would want a rifle that feeds any ammo that might be all that's available. it's unacceptable to me the BCM won't do this, especially at the price. they didn't even offer to send out a shpping label to the OP to attempt to resolve the issue. as another poster mentioned, much cheaper bushy's will feed this stuff fine.

    reliability and poor customer service are two deal killers for me when buying a gun. scratch BCM off the list.
     
  18. ugaarguy

    ugaarguy Moderator Staff Member

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    Please note that the EAG configuration is the only BCM upper set up this way - mid length gas on a 14.5 bbl. The rest of their standard (not pistol or SBR) bbls./uppers/rifles use the standard carbine length gas on a 14.5" or 16" bbl, mid length gas on a 16" bbl, or rifle length gas on 20" rifle bbls.

    For those unfamiliar, EAG is EAG Consulting, which is owned by Pat Rogers. Pat is a former Marine & LEO, and he is widely regarded as being amongst the top tier of defensive carbine trainers. The EAG bbl./upper/rifle setup offered by BCM was set up at that way from his consulting / request. Again, this is not a BCM problem at all. This is an upper set up to run true 5.56 NATO spec ammo, and true 5.556 NATO spec ammo only.

    In simpler terms this is like running 22LR subsonic or standard velocity ammo in a .22LR semi-auto rifle or pistol. Some of it will cycle the action, and some of it will not. Conventional wisdom is to run only high velocity .22LR ammo is semis unless you have found a standard velocity load that proves itself reliable in your weapon. No one freaks out at the manufacturer in those cases. This is the AR-15 equivalent.

    If you want to run SAAMI spec .223 Rem or under-spec 5.56 NATO ammo then do not buy the EAG upper, bbl, or rifle from BCM - just get any of their standard configurations.

    FWIW, every AR carbine I've owned (several from various mfrs.) has been a 16" with carbine length gas. The DDM4 I currently own is the only one with a heavy buffer, and that's only because it comes from the factory that way. Every other one has or had a standard carbine buffer, and all ran fine. As I said earlier, some 16" bbl ARs with carbine length gas do need a heavier buffer, but this is not the rule, and it's also common knowledge in the AR community. I also know this THR, and not an AR-15 focused board, so I don't expect everyone here to know that either. I hope my long winded explanations have helped.
     
  19. mc223

    mc223 Member

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    I hate to see these threads go downhill and involve any brand bashing. All mfgs might have an issue from time to time. They are operated by real people in most cases and are not infallible.

    I read that the OP fired 22LR and some Russian ammo.

    It is my opinion that the Russian ammo tends to lean towards the side of lower pressure. This may keep the harder steel cases from properly obturating to the chamber walls allowing gas to escape to the bolt area.
    This coupled with a possible partially clogged gas system(Lead and misc. crap from the ammo) would cause a short stroke as described in the OP.


    My first reaction was most likely exactly as the response from BCM.
    You paid the cash for a uber reliable rifle then feed it crap. Then wonder why. Well DUH. And then just for a topper you throw in a 22LR conversion. Double Duh.


    How do ya fix it. Well as a lesson the OP should have to take the rifle to a BCM approved gunsmith to have the gas systen properly checked and cleaned of the clog as necessary.
     
  20. mc223

    mc223 Member

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    If it was a mfg problem it would be different. This is an OP caused failure.
     
  21. MistWolf

    MistWolf Member

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    A few corrections-
    The pressure of the gases will be the same for a carbine length gas system regardless if the barrel is 14.5", 16" or even 20". What is different is how long the system will be pressurized as the longer the length of the barrel after the gas port, the longer it will take the bullet to clear the barrel. Because of the longer dwell time, the system has less time for the pressure to drop after the bullet has cleared the muzzle and before the BCG begins moving.

    Armalite was the company that pioneered the midlength gas system for 16" barrels. It doesn't "equalize the pressure", but it does two things. First, the pressure of the gases are lower as the bullet travels further down the barrel. This lowers the pressure used to operate the action. Second, the distance from gas port to muzzle is the same for a 16" mid length gas system as it is for a 14.5" carbine length gas system. This reduces dwell time slightly compared to the 14.5 carbine as the bullet's velocity is slightly greater.

    223 ammo fired in 223 chambered barrels of comparable lengths generates comparable velocities as does the 5.56 fired in 5.56 chambers. This could not be so if the 223 were not loaded to lower pressures. Fact is, SAAMI & NATO measure pressure at different points using sensors with different specifications which means the pressures cannot be directly compared. The reason the 223 is "underpowered" in 5.56 barrels is due to the longer leade of the 5.56. As the 223 is loaded to be fired safely in a shorter leade, this results in greater bullet jump before it engages the rifling. This jump increases effective case volume which in turn drops pressures & velocities.

    This is why it's unsafe to fire 5.56 ammo in a 223 spec chamber. They are loaded for the longer leade. Bullets of 5.56 ammo can engage the rifling of a true 223 chamber and cause pressures to reach dangerous levels.

    Smithwess, did you lube the carrier well, especially after shooting the 22 rimfires? If not, it's not surprising the rifle was malfunctioning. A good shot of lube would allow the crapola left in the action from the 22 rimfires to be suspended by the lube and let the carrier operate better. Give an AR a healthy shot of lube and it will amaze you at how dirty it can still run
     
  22. Zerodefect

    Zerodefect Member

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    Shoot quality ammo until it smooths out. Quit shooting .22lr thru it. Get a dedicated .22 upper for that.

    If you need to run weak ammo, then get a 14.5 with a carbine gas system. Maybe a 16" with a Carbine gas system would suit you better.

    Middy 14.5 is for a smooth shooting tactical carbine with less recoil for quiker follow up shots. But you have to run quality ammo. Noone defends themself with Wolf ammo. This is not BCM's fault. Your rifle is perfoming exactly as they usually do in my experience.

    MIDDY 14.5" DEOSN'T LIKE WIMPY, CHEAP AMMO
     
  23. Z-Michigan

    Z-Michigan Member

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    We would need exact quotes of what OP told BCM and their exact reply to even start to judge anything like that. It's not bad service if BCM tells someone an honest answer of how their product is supposed to work, even if customer didn't like it.

    Yes, because zombie SHTF is by far the most important "real world" for all of us. And in that scenario it's far more likely that someone will come across cases of weak underpowered Russian ammo in a caliber the Russians don't use, rather than say surplus US military ammo.

    Please do. Shorter wait times for the rest of us!
     
  24. steven58

    steven58 Member

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    My 16" midlength BCM (Spikes ST-T2 buffer) feeds Wolf, all the Bears, Privi, as well as a variety of commercial .223 just fine.

    I often run 500 - 1000 rounds in a day of Federal bulk HV .22 LR through a Ciener conversion kit with no problems (kids). As a CYA, at the end of a session, I then fire 3 rounds 5.56 to blow out the gas system.

    It also runs fine with Federal and Winchester MILSPEC 5.56.

    3 friends have 16" BCM carbine length systems with the same experience.

    Maybe the 16" middie, as opposed to the 14", gives me just enough extra dwell time to run the above variety of ammo?
     
  25. Jaybird78

    Jaybird78 Member

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