Confusion on 300 blkout and MD

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  • swinokur

    In a State of Bliss
    Patriot Picket
    Apr 15, 2009
    55,395
    Westminster USA
    I have an SBR. I have shot a pistol with a Sig brace.

    Not the same experience iMO. Didn't like the pistol much.

    my .02
     

    Indiana Jones

    Wolverine
    Mar 18, 2011
    19,480
    CCN
    Because the sig arm brace is ugly as hell and there's no telling when the ATF is going to change their opinion on that thing.


    Well, do it and pray it gets grandfathered. I have a Mk18 pistol and im waiting on SBR paperwork. Its way to enjoy the upper before getting a stamp.
     

    BUFF7MM

    ☠Buff➐㎣☠
    Mar 4, 2009
    13,576
    Garrett County
    But. but. but.

    I can shoot a single 5.56 round in my 300blk rifle.






    :lol2::lol2:

    photo-3.jpg

    photo-2.jpg

    photo-5.jpg

    photo-1.jpg


    300-ACC-Blackout72.jpg

    OUCH!!!
    That sucks, glad you didn't get hurt.
     
    Feb 28, 2013
    28,953
    The barrel has to be HBAR for it to be legal. I don't think there is such thing as a non-HBAR 300blk barrel, so that would tend to indicate they are good to go.

    Well, if I'm not mistaken a barrel with the bore size of .300 blk would be compromised by the M203 notch found on 5.56 barrels. So any .300 blk upper on any lower should be fine.
     

    fabsroman

    Ultimate Member
    Mar 14, 2009
    35,852
    Winfield/Taylorsville in Carroll
    Well, do it and pray it gets grandfathered. I have a Mk18 pistol and im waiting on SBR paperwork. Its way to enjoy the upper before getting a stamp.

    Why would I need to pray about anything. ATF is currently approving them as long as they are greater than 29" in length, which a 10.5" barrel should accomplish, or as Clandestine pointed out to me, a 8.5" barrel with a pinned comp on it. No prayers required. Just need to find the time to order my lower, complete the trust paperwork, and then submit the Form 1 to the ATF.

    Regarding the Sig brace, if that was the "cat's meow", nobody would be selling AR buttstocks anymore. I simply have no desire to shoot a .300 Blk or .458 SOCOM with a Sig Brace or from anything that resembles a pistol. Shooting a .50AE desert Eagle and a .44 Magnum revolver has turned me off to monster handguns.
     

    fabsroman

    Ultimate Member
    Mar 14, 2009
    35,852
    Winfield/Taylorsville in Carroll
    Well, if I'm not mistaken a barrel with the bore size of .300 blk would be compromised by the M203 notch found on 5.56 barrels. So any .300 blk upper on any lower should be fine.

    The M203 notch isn't the only thing that makes a barrel non-HBAR. I believe the diameter of the barrel is also taken into consideration. It must be .750" diameter throughout the barrel. An example of a barrel that is close, but not quite, is the JP Rifle .300 Blk barrel. It measures .750 at the gas block but only .740 forward of the gas block.

    http://www.jprifles.com/buy.php?item=JPSM300BLK-16L8

    Wish I had the time to find more examples, but the JP is the one I know off the top of my head.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    MD AG stated that a copy is one with completely interchangeable internal parts.

    If you take a 5.56 AR and a .300 BLK AR any/all the internal parts will swap and the firearms will both be functional. So, to me, a .300 BLK would still be banned if not an HBAR.

    I have always read it as I can take any one part (at a time) from one and put it in the other. And NOT requiring that a number of parts be swapped as a group to make it work. So piston ARs are fine, as you need to swap a set of parts to make it work.

    As with many things in life, it is up to YOU to decide how far you are willing to push things.
     

    TyFromMD

    Ultimate Member
    Mar 31, 2011
    3,804
    Maryland
    Thank you very much. Trying to find a 458 SOCOM barrel, much less one at 10.5" was a nearly impossible. That website is wonderful when it comes to 458 SOCOM.


    Glad I could help. Let me know what you think. A 458 socom sbr is definitely in my future plans.
     

    Bolts Rock

    Living in Free America!
    Apr 8, 2012
    6,123
    Northern Alabama
    No calibers have been banned. Except .40.

    They aren't banned, Chad's just hoarding them.

    I'm going to do as Ty suggested, and go the SBR .300 Blk route with a 10.5" barrel. Might do that on a .458 SOCOM too, but finding a barrel for that rifle is extremely tough (i.e., I have yet to find one).

    Thank you very much. Trying to find a 458 SOCOM barrel, much less one at 10.5" was a nearly impossible. That website is wonderful when it comes to 458 SOCOM.

    Not that hard to find a .458 SOCOM barrel, 10.5" may be an issue but I really don't think you're going to like it with a 10.5" barrel.
     

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    TyFromMD

    Ultimate Member
    Mar 31, 2011
    3,804
    Maryland
    They aren't banned, Chad's just hoarding them.







    Not that hard to find a .458 SOCOM barrel, 10.5" may be an issue but I really don't think you're going to like it with a 10.5" barrel.


    From Wilson Combat's page "The .458 SOCOM achieves optimum ballistic performance in barrel lengths shorter than 16” so there is no need for longer, less portable barrels."

    I believe with the right stock and muzzle device or can, that a 10.5" or 12.5" 458 socom will be very comfortable.
     

    Lou45

    R.I.P.
    Jun 29, 2010
    12,048
    Carroll County
    No calibers have been banned. Except .40.

    Revised:

    .40 STV (Sandy Tactical Vagina).:D

    I thought the requirement for an HBAR was for a AR15 or copy. The 300 blk is neither of those.

    Not being argumentative, just trying to clarify for myself.

    Right, your second sentence.

    Right, but the 300blk is interesting in that the only part you have to change is the barrel. I wouldn't want to be the test case on the copycat law. But in the end I think it is irrelevant given that it is an HBAR.

    Right.
     

    fabsroman

    Ultimate Member
    Mar 14, 2009
    35,852
    Winfield/Taylorsville in Carroll
    I ain't stoopid enuf to make a pistol in that caliber, that's a rifle.

    Thanks for all the pics.

    I have a hard time thinking of a .223 in a pistol. No way would .458 SOCOM be a pistol. Then again, SBR does have Rifle in it.

    Won't be using the .458 SOCOM for anything but close range stuff, like in the house, so I don't really want a 16"+ barrel on it. Maybe not a 10.5" barrel, but definitely something shorter than 16". I'll build the .300 Blk first, see how I like it at 10.5", see how much barrel length I need for a full powder burn in a .458 SOCOM, and then attempt to figure out what length barrel I want for the .458 SOCOM.

    The .458 standing next to the .223 makes the .223 look small. Then again, I've done most of my deer hunting with a .300 Win Mag over the past 20 years, so when I saw my first .223 case I thought it was puny.
     

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