Lapping AR15 Uppers

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  • rbird7282

    Ultimate Member
    MDS Supporter
    Dec 6, 2012
    18,716
    Columbia
    Ok, this is all good stuff - at least there seems to be some consensus on this forum. :lol2:

    Regarding the lapping tool, is the Wheeler tool decent enough, or are there others that are better? I'm not opposed to spending some money on tools if I feel it's warranted, although I don't know how many more ARs I'm going to build.

    How necessary is it to bed the barrel? Very necessary? Necessary only for improved accuracy? Just curious.

    The barrel on this first build was pretty snug in the upper, which was a PSA blem upper that I got on the cheap years ago and finally decided to put to use. All I know is that the rifle is a pretty solid shooter - my son and I are doing 20 shot groups at 50 yards that aside from the odd flyer which is probably our fault, are slightly bigger than a quarter. Is that super accurate? Nope, but that could also be attributed to the ammo - 55 gr reloads out of a 1:7 twist barrel. (1:9 would be better for 55 gr)

    I'll employ some of this on the next build - I've got all the parts on hand or in the mail, so I'll probaby pick up a lapping tool. The upper on the way is an Aero upper, so hopefully it's pretty solid and won't need a lot of work, and hopefully the barrel fits pretty snugly.


    I use the Wheeler lapping tool and it works just fine. Personally I always bed the barrel even if it’s a tight fit.
    I just helped a friend do a build and he had an Aero upper and lower. Barrel fit was snug but I still used the bedding compound.
    Even if the fit is snug, bedding it takes away any gaps no matter how small and will minimize barrel movement inside the upper especially when the barrel gets hot.


    Sent from my iPhone using Tapatalk
     

    teratos

    My hair is amazing
    MDS Supporter
    Patriot Picket
    Jan 22, 2009
    59,838
    Bel Air
    One caveat, beware of thermal fit uppers like BCM. You will have to heat it up to lap it, or turn down a lapping tool a bit to get it to fit correctly.
     

    DaemonAssassin

    Why should we Free BSD?
    Jun 14, 2012
    23,999
    Political refugee in WV
    Ok, this is all good stuff - at least there seems to be some consensus on this forum. 2:



    Regarding the lapping tool, is the Wheeler tool decent enough, or are there others that are better? I'm not opposed to spending some money on tools if I feel it's warranted, although I don't know how many more ARs I'm going to build.



    How necessary is it to bed the barrel? Very necessary? Necessary only for improved accuracy? Just curious.



    The barrel on this first build was pretty snug in the upper, which was a PSA blem upper that I got on the cheap years ago and finally decided to put to use. All I know is that the rifle is a pretty solid shooter - my son and I are doing 20 shot groups at 50 yards that aside from the odd flyer which is probably our fault, are slightly bigger than a quarter. Is that super accurate? Nope, but that could also be attributed to the ammo - 55 gr reloads out of a 1:7 twist barrel. (1:9 would be better for 55 gr)



    I'll employ some of this on the next build - I've got all the parts on hand or in the mail, so I'll probaby pick up a lapping tool. The upper on the way is an Aero upper, so hopefully it's pretty solid and won't need a lot of work, and hopefully the barrel fits pretty snugly.
    Would you like to slide over and use my tools? I have a lapping tool from Brownell's that has done well by me on more uppers than I can remember.
     

    Racer Doug14

    Thread killer
    MDS Supporter
    Patriot Picket
    Feb 22, 2013
    8,008
    Millers Maryland
    DaemonAssassin also helped me learn the pros of lapping the upper. The carbine we did is super accurate. I bought my own lapping tools for ar15&ar10s. done this one this morning.
    20220618_085339.jpg
     

    teratos

    My hair is amazing
    MDS Supporter
    Patriot Picket
    Jan 22, 2009
    59,838
    Bel Air
    Nicely done. DA is a good man, and very lovable.
    What you do behind closed doors is your business.

    I use a lot of BCM uppers. After I tore the threads off, I got another lapping tool and took a little metal off. I have one for BCM, and one for “other” uppers.
     

    trickg

    Guns 'n Drums
    MDS Supporter
    Jul 22, 2008
    14,719
    Glen Burnie
    I lapped the upper on my last build, but I haven't had a chance to get it to the range yet to see if it even mattered. I'm going to try to get it out tomorrow.
     

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