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Swapping AR BCGs?

Discussion in 'Rifle Discussion' started by RedneckRampage, May 6, 2015.

  1. RedneckRampage

    RedneckRampage Newberg Well-Known Member

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    Is it ok to swap complete BCGs between two AR15s? I'd like to put the better one in one of my other rifles. Do I need to have it head spaced or anything? Both are mil-spec.
  2. filsonhand

    filsonhand In the Silicon Forest Smooth as a Rhino 2015 Volunteer 2016 Volunteer

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    As long as they are mil spec you are good to go :)
    mjbskwim likes this.
  3. Garg

    Garg east of portland metro Hold my beer..... watch this Bronze Supporter

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    I swap them willy nilly all the time. Never had a problem.
    oli700 likes this.
  4. Classic

    Classic Federal Way WA Well-Known Member

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    I built an AR pistol and used the BCG out of my Daniel Defense which got updated with a NiB BCG. Put a Geissele trigger in the DD and it's trigger went in the pistol, same with the charging handle.
    One of the great things about AR's is that they are the lego's of guns! I have yet to find a part that wasn't interchangeable ;)
  5. Lange22250

    Lange22250 Milwaukie Active Member

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    A local PD which shall remain unnamed has an armorer who failed to pay attention to detail. He cleaned all the rifles at the same time and stripped the rifles down and mixed the parts together when cleaning them, then reassembled them randomly. Over the next few months they had a sharp rise in the number of failed and broken bolts.

    It makes sense that metal parts that contact each other will "wear together" over time since the initial specs were probably not perfect.

    Changing bolt carriers probably not a big deal but the bolt it's self could be problematic.
  6. Garg

    Garg east of portland metro Hold my beer..... watch this Bronze Supporter

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    but the bolt it's self could be problematic.

  7. Gator Monroe

    Gator Monroe Southern Cascades Well-Known Member

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    Go & No Go Gages are handy for this
  8. IronMonster

    IronMonster Washington Opinionated Member Diamond Supporter

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    As others have stated, you should not have a problem.

    BY THE BOOK you should always check headspace when you put a new bolt in a rifle IN THE REAL WORLD it probably happens at most reputable shops and retailers but average folks rarely do and if you go searching the internet looking for people who had headspace issues with good parts you wont find many.

    I have a 11pc 5.56 National match head space gauge set. I have checked probably 40, all of them where not even close to the outside of the range. I have even taken a bolt and headspaced it to 10-ish different barrels, same thing. Good to go.
    ron and oli700 like this.
  9. CV-66

    CV-66 Brush Prairie Active Member

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    I've swapped bolts between rifles and have only experienced failure to go into battery of those with chambers cut at the minimum spec (a'la kreiger) and also when using the plated (boron and chrome). Sometimes that little bit of plating can keep a round from chambering. I've used a series of headspace gauges over the years and have found measurements all over the board. Luckily though, even those closing on nogo still refuse my colt field reject. I agree with ironmonster. You know something though? Why is it thought to be ok to do this with ar15's yet most people cringe at the thought of swapping bolts between similarly chambered remington 700's or ruger m77's?
    ron likes this.
  10. Stomper

    Stomper Oceania Rising White Is The New Brown Silver Supporter

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    In my Army days, swapping bolts (not the carrier) between weapons was a no-no, because of "signature wear".
    spectra and Caveman Jim like this.
  11. Callidus98

    Callidus98 Portland Member

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    Brownells sells the gages for about $30 each.

    The other probably have more experience so if they say you won't likely have a proem with quality parts I believe them.

    But I still check mine. Seems like a good idea for piece of mind, safety, and reliability.
  12. Dean Armer

    Dean Armer Monmouth New Member

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    There is a lot of info missing. Are they the same brand? How many rounds through each? Have you owned the rifles since they were new? The lower the round count the better.

    Remember that mil spec still has tolerances and not all manufacturers are diligent. There is no "mil spec police". If you don't have a way to check head space leave the bolts with the matching barrel extension.

    Best advice - You should always check the head space. Safety first.
  13. Reno911

    Reno911 Hillsboro Well-Known Member 2015 Volunteer 2016 Volunteer

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    Having built and maintained many ar15s. Swapping bolts is a finicky thing. If the bolt has had a few thousand rounds in one gun, it stays with that gun. If it needs replacement, then replace it. Even a new bolt on a multi thousand round gun can lead to failures.

    Most of the failures I've seen with this are bolt battery related. Bolt not mating up well with the extension.

    That is only once and a while though. Usually there is no issue swapping bolts on guns with round counts in the hundreds.
    Dean Armer likes this.