Non-223/5.56 AR build info

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  • jimbobborg

    Oddball caliber fan
    Aug 2, 2010
    17,108
    Northern Virginia
    Like I said, only those 3 parts are different.

    You may choose to play with the buffers, for example I prefer an H2 buffer in my 6.8, but it runs fine with a standard buffer.

    Yup. I ran a standard carbine buffer in one of my 6.8 builds, and the other uses an A2 stock, so a standard rifle buffer works, too.
     

    the Javid

    Part time baby killer
    Mar 20, 2012
    199
    Bowie
    He I don't mean to derail the thread or anything but does any one know how worried I should be about firing corrisive ammo through a melonite treated ar chambered in 5.45? Keep in mind I clean my weapons til there is no carbon to be found by military style inspection shortly after I arrive home from the range. The range is usually the myrtle grove shooting range in la plata and my house is between bowie and crofton. Usually takes around 45min-1.25hours. Also should I use more than just a bore snake to clean the barrel?
     

    jimbobborg

    Oddball caliber fan
    Aug 2, 2010
    17,108
    Northern Virginia
    Any larger pistol calibers out there ? 357 / 44 mag ? If I do a pistol/commando I want something different.

    Uppers are available in 10mm and .45 ACP and .410. The problem with the magnums you listed is they are rimmed cartridges, so feeding through AR mags is a problem.
     

    Forest

    The AR guy
    Jul 13, 2011
    985
    Uppers are available in 10mm and .45 ACP and .410. The problem with the magnums you listed is they are rimmed cartridges, so feeding through AR mags is a problem.

    Talk to Tony at Tromix, he's done uppers in magnum calibers. The man is a wizard at unusual AR variants and calibers.
     

    ktigerJ

    Ultimate Member
    Jun 5, 2013
    1,333
    I've seen in this thread talk about the 6.8 spc. AR with standard and H2 buffers. I am wondering about the 7.62x39mm upper. Does anyone have any recommendation for it?
     

    Respen33

    Cover Fire Specialist
    Jun 24, 2012
    189
    Severn, MD
    Standard Carbine Buffer and Spring works fine.

    My reading told me the standard vs H2 is totally dependent on the gas return and powder charge you use. The more pressure your round throws it may not be as crucial as the gas return will be sufficient to rack the next round. The larger the round the less gas can return meaning it may have issues so the coil system you use comes into play.
     

    photoracer

    Competition Shooter
    Oct 22, 2010
    3,318
    West Virginia
    Just thought I'd add to this. There's actually a third, not supported by many, called the 6.8x43.

    Magazines are made by Barrett, PRI, and C-Products. The Barret is a true 30-round magazine, stainless steel, and cartridges must be 2.260" COAL or less to fit in Barrets. C-Product mags are basic, stainless steel magazines and hold 25, 15, and 5 rounds. The max COAL I've had work with these mags is 2.285". PRI makes stainless steel mag, 25, 15, and 5 rounds. You can load out the cartidge to 2.300" COAL. Of the three magazine makers, Barret makes the most reliable, followed by PRI and then C-Products.

    You will want the PRI mags if you intend to try out the new Berger 140g match ammo that is supersonic at 1000 yards as they are the only mags that support the increased OAL of that cartridge.
     

    Lostinbmore

    Junior grade mop slopper
    Dec 19, 2012
    250
    Baltimore
    Question about the 6.8 as well. I noticed there is no mention about the lower. I am assuming a 5.56 lower will work. Are the 6.8 mags fitting in the mag wells ok?


    Sent from my iPhone using Tapatalk
     

    BradMacc82

    Ultimate Member
    Industry Partner
    Aug 17, 2011
    26,177
    Question about the 6.8 as well. I noticed there is no mention about the lower. I am assuming a 5.56 lower will work. Are the 6.8 mags fitting in the mag wells ok?


    Sent from my iPhone using Tapatalk

    No dimensional difference, only a diff't follower in the magazine, and a slight reduction in total capacity.
     

    ktigerJ

    Ultimate Member
    Jun 5, 2013
    1,333
    Picked up my new Gen II C Products AR 7.62x39 mags. So far they are great. There seems to be a little hang when running them through but way better than the ASC's I have. Can't wait to get out and shoot it now.
     

    ktigerJ

    Ultimate Member
    Jun 5, 2013
    1,333
    For anyone following this the mags ran flawlessly. I only had steel cased Herter's on hand. It was a joy to shoot. I ran about 130 rounds through the AR and four of the five mags.
     

    kenpo333

    Ultimate Member
    Industry Partner
    MDS Supporter
    Mar 18, 2012
    3,322
    Salisbury Maryland
    two of mine

    the top is a 5.7 with the brass catcher in the mag well and it will hold over 50 spent cartridges.

    bottom is my aark which has a real easy barrel(caliber) change.
     

    Attachments

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    Mar 7, 2014
    23
    Required parts
    1) 9mm upper receiver group
    2) 9mm magazine well adapter OR a 9mm lower receiver
    3) 9mm buffer
    4) 9mm magazines


    Notes:
    - If you decide to buy an upper receiver and add a 9mm barrel, there will be no shell deflector as is normally integrated on dedicated 9mm uppers.

    - For functionality it is accepted that either a ramped bolt group carrier OR a 9mm hammer is a necessity.


    Reference:
    http://www.mdshooters.com/showthread.php?t=59223
    http://www.mdshooters.com/showthread.php?t=54359


    Disclaimer:
    I found this information through a few searches, if it's incorrect, please say so and I'll VERY gladly edit this post. I'm just trying to save someone else the time and hassle I've spent searching. :thumbsup:


    EDIT:

    If using the pro-mag mag block (which apparently is a copy of the old C-products mag block), you may have to dremmel/file down the feed ramp to accommodate the incorrect height of the ramps. I found this out with my own pro-mag block and some research on the web about common feeding issues. If you try to use it with the stock height, you'll notice rounds slamming into the ramp instead of feeding into the chamber. I'll try to post some pictures of the modified block later.

    8469711940_d265f7e08f_c.jpg





    8469713642_88b922c8ed_c.jpg
    Sweet baby Jesus I need one of those!!!!!!!!!!!!!!!!!!!!!!
     

    photoracer

    Competition Shooter
    Oct 22, 2010
    3,318
    West Virginia
    Just thought I'd add to this. There's actually a third, not supported by many, called the 6.8x43.

    Magazines are made by Barrett, PRI, and C-Products. The Barret is a true 30-round magazine, stainless steel, and cartridges must be 2.260" COAL or less to fit in Barrets. C-Product mags are basic, stainless steel magazines and hold 25, 15, and 5 rounds. The max COAL I've had work with these mags is 2.285". PRI makes stainless steel mag, 25, 15, and 5 rounds. You can load out the cartidge to 2.300" COAL. Of the three magazine makers, Barret makes the most reliable, followed by PRI and then C-Products.
    6.8x43 is the official designation and generic general purpose name for 6.8. There are or have been 6 different chambering of the 6.8, however only the SPC II, Noveske Mod 1, and 6.8x43 ERP can use the higher pressure rounds of the SPCII spec. All rounds will fit and fire out of any of them its just that some only meet the SAAMI spec and can't take the higher pressure of say SSA Tactical loads. All your mag info is correct. I have had no issues with the 2 brands I currently use (C-Products and PRI)
     

    iH8DemLibz

    When All Else Fails.
    Apr 1, 2013
    25,396
    Libtardistan
    Since this thread got bumped, I will talk about my 300 BLK rifle for a bit. Rifle tube, buffer, and spring.

    Built it with a 16" AR Stoner barrel. The barrel gas port came factory drilled at .109 inches.

    I only reload for this rifle using cut down .223 brass. No factory ammo for testing as I was already at max load data and then some.

    Using 125, 150, and 180 grain bullets, it would only cycle correctly if I went over max load data by .8 grains or so of H110. Doesn't seem like much, but it puts the pressure right at SAAMI max of 55,000. Was getting flattened primers and oversized primer holes in the case head. Could press a primer in place with my thumb.

    Finally got off my butt and opened the gas port in the barrel up some. At .125 inches, it cycles all three bullet weights at just above the starting end of the load data. Works like a dream now and love reloading for it and shooting it.

    I'm assuming the barrel was designed with a suppressor in mind where a bit of back pressure would aide in cycling.

    Hope this helps those who are building 300 BLK guns in the future.
     

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