Dedicated.22lr upper?

Discussion in 'Long Guns - Rifles & Shotguns' started by dsdmmat, Sep 14, 2018 at 12:19 PM.

  1. dsdmmat

    dsdmmat Donut Master Yearly Shot Winner Monthly Shot Winner

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  2. togmaster

    togmaster .338 Win Mag

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  3. ProgSpear

    ProgSpear .308 Win

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    OK 2 questions...

    1) how well will an aluminum barrel hold up, even with a "slow" 1:16 twist?
    2) what problems will you run into shoving lead rounds through a relatively "fast" 1:8 twist standard barrel?
     
  4. GOYABEAN

    GOYABEAN .450/400 Nitro Ex

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  5. BDinPutnam

    BDinPutnam 6.5 Creedmoor Monthly Shot Winner

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    This concept, one way or the other, has been on my to do list for a looong time.

    :popcorn:
     
  6. dsdmmat

    dsdmmat Donut Master Yearly Shot Winner Monthly Shot Winner

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    7075 is some pretty tough stuff. It would probably last longer than I will.
     
  7. dsdmmat

    dsdmmat Donut Master Yearly Shot Winner Monthly Shot Winner

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    BDinPutnam and GUNSICK like this.
  8. BDinPutnam

    BDinPutnam 6.5 Creedmoor Monthly Shot Winner

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    Jumping in again for a sec-

    Generally agree but I want to do mine featureless. How do you think a pin/weld would do on that barrel? Not trying to stir the pot, I'm genuinely curious as I am no gunsmith or metalurgist.
     
  9. dsdmmat

    dsdmmat Donut Master Yearly Shot Winner Monthly Shot Winner

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    The same as every other barrel. I just blind pin mine, never welded them up.
     
    BDinPutnam likes this.
  10. BDSKJCHRIS

    BDSKJCHRIS .40 S&W

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    i built mine using a cmmg bolt and 16.1" barrel combo. It shoots great and hasn't given me any problems yet so i would definitely recommend it.

    warning lots of text here:

    i am posting this review for anyone who is on the fence about a dedicated .22lr AR or AR upper to swap onto an existing lower. so first off here are the build specs:

    • BCM stripped upper receiver

    • CMMG M4 profile .22lr barrel

    • CMMG dedicated .22lr BCG, (not the 5.56 conversion kit)

    • CMMG .22lr charging handle

    • CMMG mags

    • Taccom pressure plug

    • AAC engraved Knights Armament URX 3.1 rail

    • Vortex Sparc II bright red dot sight
    Assembly: pretty straight forward here but a word of caution to anyone building on one of the newer bcm stripped uppers, they are not kidding about the fit of the barrel extension being tight. My advice is to put some aeroshell 33ms grease on the extension and throw the barrel in the freezer for at least 4 hours, (i will leave it overnight in the future). Again, grease the id of the upper with 33ms then place the stripped upper in the oven at 200 degrees for 15-20 minutes and have a heat gun ready to go.

    aluminum cools pretty fast so get a pair of welding glove on and get ready to move fast, take the barrel out of the freezer and have it ready in one hand, then open the oven and with the other GLOVED hand take the upper out and quickly insert the barrel extension into the upper, making sure to align the indexing pin with the notch in the upper. if the upper cools down and the barrel extension isn't fully seated, grab the heat gun and apply heat to the middle of the upper while applying pressure or tapping with a rubber mallet. careful not to wreck your upper or the crown of your barrel.

    rail installation: This was easy, just remove the bottom half of the rail, grease all threads with aeroshell 33ms, (kac calls for blue loctite but i decided not to use it to make future disassembly easier and it is only a .22 so i am not worried about anything falling apart) place the barrel nut in the rail and start it (3 revolutions to be sure it is aligned), slide the top half over the barrel and thread the rail onto the upper receiver. Thread the rail onto the upper until it bottoms out and them back it off to align the 12 o'clock picatinny rail with the rail on the upper. in order to keep the rails aligned, i have a couple of 1" scope rings on a short section of round bar, there are other tools for this but this is what i use because it is what i had and it has worked for every build. tighten the barrel nut to 55 ft/lbs instructions here

    Function: to assemble, just insert the charging handle and .22lr BCG as you normally would, the bolt carrier has a collar that will lock into place around the barrel. insert the pressure plug into the buffer tube, flat side goes against the buffer face, tapered end goes against the BCG. assemble the upper and lower with the takedown pins and you are good to go.

    shooting: i put about 200 rounds through it on it's first range trip, not a single hiccup, and it is a blast to shoot, (this is my first ever .22lr). the mags are easy to load, (loading tabs would be nice though). the vortex red dot works very nicely and i learned that i have astigmatism.

    one thing worth noting is that these mags do not engage the bolt catch. However, on the last round the follower does keep the bolt from going into battery and reloads are quick and easy.

    if you are on the fence about building an AR-22, i would say go for it and use this bolt/barrel combo, you won't regret it.
     
    ProgSpear likes this.
  11. Prudii

    Prudii .357 mag

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