556 SBR upper

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    Grandmaster
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    Sep 22, 2008
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    Kokomo
    I'm getting ready to build my first SBR...

    Yay me.

    There's a lot to weed through. I'm wanting to build around a suppressor, and there's no shortage of those either. Huntertown is best priced, but I don't like the minimum 11.5 barrel requirement and I don't like that they don't offer quick connect. So, I'm leaning towards YHM or AAC.

    I want 10.5 but what about twist rate? Then, there's this 223 wylde barrel, are those better?

    Help me Obi-wan, you're my only hope.
     

    Fargo

    Grandmaster
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    13   0   0
    Mar 11, 2009
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    In a state of acute Pork-i-docis
    I am presuming this will be an AR? If you want to run a can on an AR SBR, that is one of the times I would seriously consider a piston upper.

    I've played with canned short impingement AR's and they have some issues. They are immensely overgassed with the can and blow crap back into your face. They also have a fickle pressure curve on the short system and many take a good bit of work to get running. Gas port size and different buffers usually can remedy this but I still find them unpleasant to shoot and the unholy amount of carbon ends up in the action in no time.

    I personally would probably look at a piston if only to keep the crap out of my face and the action.

    In a SBR, I would stick with the looser 5.56 chamber. I know the wylde can fire 5.56 and is slightly more accurate, but we are talking about a short gun anyway which by nature of the short pressure curve is going to exctract somewhat hard. I would stick with 5.56.
     

    rvb

    Grandmaster
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    Jan 14, 2009
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    IN (a refugee from MD)
    what about twist rate? Then, there's this 223 wylde barrel, are those better?

    what bullets do you plan on using?
    9 to 7 twist, unless you are planning to shoot something at either end of the std weight spectrum (50 grn, or 75+). 8 is a good compromise. Mine is a 7 twist and I use 55s to 75s. you'll want to check any new load for signs of keyholing and not being stable before putting them through your can, esp the shorter you go.

    wylde is fine, I don't know what being an SBR would have to do with avoiding it.

    As for gas, you can also go w/ an adjustable gas block vs piston.

    -rvb
     
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    Fargo

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    In a state of acute Pork-i-docis
    wylde is fine, I don't know what being an SBR would have to do with avoiding it.

    IME canned SBRs extract faster and harder than most any other AR, with there often being signs on the case rim that the extraction cycle has begun prior to the chamber letting go of the case. I would not think that a tighter toleranced chamber would be helpful in keeping extraction reliable.
     

    rvb

    Grandmaster
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    Jan 14, 2009
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    IN (a refugee from MD)
    IME canned SBRs extract faster and harder than most any other AR, with there often being signs on the case rim that the extraction cycle has begun prior to the chamber letting go of the case. I would not think that a tighter toleranced chamber would be helpful in keeping extraction reliable.

    the main difference between 5.56, 223, and wylde chambers primarily has to do with the freebore area (area in front of the case mouth where the bullet sits, before it hits the rifling). Wylde has more lead length before the bullet hits the throat and a shallower throat angle sim to 5.56. The only thing "tighter" about it is in that freebore area, it has the .223 freebore diameter. It's not a "tighter" chamber around the case that's going to make a difference in extraction of the case (of course reamers vary by makers).

    -rvb

    edit: Examples of some reamer dimensions. Note dimensions G, N, and R.
    http://ar15barrels.com/data/223-556.pdf
     
    Last edited:

    Fargo

    Grandmaster
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    Mar 11, 2009
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    In a state of acute Pork-i-docis
    the main difference between 5.56, 223, and wylde chambers primarily has to do with the freebore area (area in front of the case mouth where the bullet sits, before it hits the rifling). More room before the bullet hits the throat and a shallower throat angle. It's not a "tighter" chamber around the case that's going to make a difference in extraction of the case (of course reamers vary by makers).

    -rvb

    Ah, I see. For whatever reason, I thought that the wylde was dimensionally tighter in the case area.
     

    rvb

    Grandmaster
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    4   0   0
    Jan 14, 2009
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    IN (a refugee from MD)
    Ah, I see. For whatever reason, I thought that the wylde was dimensionally tighter in the case area.

    common misunderstanding. cartridge/chamber dimensions are the same for all. It's that freebore dimension that causes people to worry about running 5.56 in a .223 chamber... less room for the bullet to jump and a steeper throat angle could mean higher pressures. Note many .223 "match" chambers look more like 5.56 in the freebore (longer lead for long heavy bullets)

    -rvb
     

    Dog1

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    Feb 15, 2010
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    Clark County, Indiana
    I'm getting ready to build my first SBR...

    Yay me.

    There's a lot to weed through. I'm wanting to build around a suppressor, and there's no shortage of those either. Huntertown is best priced, but I don't like the minimum 11.5 barrel requirement and I don't like that they don't offer quick connect. So, I'm leaning towards YHM or AAC.

    I want 10.5 but what about twist rate? Then, there's this 223 wylde barrel, are those better?

    Help me Obi-wan, you're my only hope.

    1. Stay away from Huntertown. Save some more and get a better can. I have a Liberty Torch QA. Quick attach and it's a rock solid mount.

    2. IMO 12.5" is the sweet spot for a SBR, still handy in tight spots and will preform great at extended ranges. Run it with a 1/8 barrel and a Wylde chamber.

    DSCN2591_zpsfc5d1f1f.jpg


    Here is mine, 12.5" White Oak Armory 1/7 barrel with a Wylde chamber, Micro MOA adjustable gas block, Liberty Torch QA suppressor. All I shoot is my reloads, 75 and 77 gr Hornady's. At all ranges, 100 and in to 400 yards, rings the steel every time if I do my part.

    I have built everyone of my SBR uppers and all of the uppers that I shoot the can on. All run 100%, no matter how many rounds I fire through it at the range. If you want, PM me with any questions on anything I have posted.
     
    Last edited:

    Dog1

    Master
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    Feb 15, 2010
    2,661
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    Clark County, Indiana
    IME canned SBRs extract faster and harder than most any other AR, with there often being signs on the case rim that the extraction cycle has begun prior to the chamber letting go of the case. I would not think that a tighter toleranced chamber would be helpful in keeping extraction reliable.

    That can be "fixed" with an adjustable gas block. With my Micro MOA block, there is no signs of stress on the cases and it dumps the brass in a nice tight pile at about 3 o'clock, 5 feet away.
     

    jd4320t

    Grandmaster
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    23   0   0
    Oct 20, 2009
    22,891
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    South Putnam County
    You'll be fine with a 10.5" barrel. A couple years ago I watched a guy ring a 6" steel plate at 400 yards easily. His optic was an Aimpoint Micro.

    I'll be honest. I don't have a lot of experience with 5.56 suppressors. The HA I heard last weekend left me disappointed. It was not hearing safe so I began to question if it's worth it. I was going to go HA but not anymore.
     

    dudley0

    Nobody Important
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    99   0   0
    Mar 19, 2010
    3,725
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    Grant County
    I haven't used a meter but my HTA 5.56 can sure seems hearing safe to me.

    Maybe I am just too deaf to realize the difference but I have dumped a few rounds through it with other people around as well.
     

    Josh Ward

    Master
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    81   0   0
    Feb 13, 2008
    1,538
    38
    Fortville/Greenfield
    Second the avoiding Huntertown, lots better products out there, not mention MUCH MUCH better customer service.

    I'm a big fan of 10.5" with a can. It'll reach out to 300-400 easy on man sized targets if needed. That being said I've handled and shot a suspressed 7.5" that performed GREAT.....
     
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