UZI Talk Forums
+ Reply to Thread
Results 1 to 20 of 20

Thread: Installing a M-10 Stock on a Semi Auto Open Bolt MAC-10

  1. #1
    Registered User
    Join Date
    Oct 2018
    Posts
    22

    Installing a M-10 Stock on a Semi Auto Open Bolt MAC-10

    As title states, I came across a stock for a MAC-10, and am seriously thinking of SBRing my semi auto open bolt RPB MAC-10 45 ACP.

    I have a few questions for some of you experts here, first is there a difference in sizes between the MAC-10 stocks?

    My second question is, after reading some old threads on here it looks that there is some semi sear could pose a issue for fully collapsing the stock if I were to install one. Has anyone had personal experience with installing a collapsing wire stock on a semi auto cobray M-10?

    Last question is, is the welding block that allows the stock to function permantely welded in place or is it just held in place by the large roll pin?
    https://www.ftfindustries.com/mm5/me...gory_Code=MCHP


    All advice/info is greatly appreciated, I can send pictures of what I am working with if need be.

  2. #2
    UZI Talk Life Member
    hkg3k's Avatar
    Join Date
    Aug 2005
    Posts
    337
    Quote Originally Posted by CobrayStinger View Post
    As title states, I came across a stock for a MAC-10, and am seriously thinking of SBRing my semi auto open bolt RPB MAC-10 45 ACP.

    I have a few questions for some of you experts here, first is there a difference in sizes between the MAC-10 stocks?

    My second question is, after reading some old threads on here it looks that there is some semi sear could pose a issue for fully collapsing the stock if I were to install one. Has anyone had personal experience with installing a collapsing wire stock on a semi auto cobray M-10?

    Last question is, is the welding block that allows the stock to function permantely welded in place or is it just held in place by the large roll pin?
    https://www.ftfindustries.com/mm5/me...gory_Code=MCHP


    All advice/info is greatly appreciated, I can send pictures of what I am working with if need be.
    Why not alter for an arm brace and save the $200 stamp and wait? It may not be your objective, but I'd predict it would ad value vs a SBR.
    hkg3k
    Browning, Maxim, Vickers
    Beltfeds: Real Machineguns

  3. #3
    UZI Talk Life Member
    zipakna's Avatar
    Join Date
    Jun 2011
    Location
    Virginia Beach Virginia
    Posts
    1,661
    i wonder if it would actually go through. since you are submitting a form 1, making you a manufacturer, and are applying to 'Make And Register a Firearm', though your intent is to make an SBR, the outcome firearm would be a open bolt firearm made after 1982.

  4. #4
    Registered User
    Join Date
    Apr 2020
    Posts
    44
    I considered SBR, but did a few ‘rehearsals’ around my home. I decided the carbine configuration is maneuverable enough that SBR is not worth the hassle/cost to me.

    For those of you willing to endure the process to have these things, my hat’s off to you.

  5. #5
    UZI Talk Supporter
    sniperdoc's Avatar
    Join Date
    Jan 2015
    Location
    TN
    Posts
    4,655
    Quote Originally Posted by zipakna View Post
    i wonder if it would actually go through. since you are submitting a form 1, making you a manufacturer, and are applying to 'Make And Register a Firearm', though your intent is to make an SBR, the outcome firearm would be a open bolt firearm made after 1982.
    That's an interesting hypothesis

  6. #6
    Registered User
    Join Date
    Jul 2018
    Posts
    531
    Quote Originally Posted by hkg3k View Post
    Why not alter for an arm brace and save the $200 stamp and wait? It may not be your objective, but I'd predict it would ad value vs a SBR.
    Please tell me youre joking. The open bolt mac is a collector piece. A modern brace is not going to add value. SBRing it may hurt the value too, since it now requires a stamp.

    I think zipakna is right about making an open bolt semi auto after 1982.

  7. #7
    UZI Talk Life Member
    hkg3k's Avatar
    Join Date
    Aug 2005
    Posts
    337
    Quote Originally Posted by Fishman View Post
    Please tell me youre joking.
    Nope...not joking.

    Quote Originally Posted by Fishman View Post
    The open bolt mac is a collector piece. A modern brace is not going to add value.
    Collector piece?...maybe to some, but not in my AO. You just never know what will add value to the right audience...regardless, my point was relative to the dip in value SBRing would bring.

    Quote Originally Posted by Fishman View Post
    SBRing it may hurt the value too, since it now requires a stamp.
    I would bet on it...most buyers are attracted to the OB MACs in the first place because they're "no-stamp with potential."

    Quote Originally Posted by Fishman View Post
    I think zipakna is right about making an open bolt semi auto after 1982.
    Not that I agree with the premise...but IMO the more elegant solution to CobrayStinger's want (without stamp) is an arm brace. Alteration may or may not be required.
    Last edited by hkg3k; 04-28-2020 at 03:46 PM.
    hkg3k
    Browning, Maxim, Vickers
    Beltfeds: Real Machineguns

  8. #8
    UZI Talk Life Member

    Join Date
    Mar 2006
    Location
    Southern New Hampshire
    Posts
    1,970
    Quote Originally Posted by zipakna View Post
    i wonder if it would actually go through. since you are submitting a form 1, making you a manufacturer, and are applying to 'Make And Register a Firearm', though your intent is to make an SBR, the outcome firearm would be a open bolt firearm made after 1982.
    To be clear, if registering a Title I firearm to a Title II firearm that is a change in configuration. A change in configuration does not change the fact that the item remains a firearm built and logged in or registered by the original manufacturer. As far as the open bolt part, if the original pistol was home made there would need to be documentation as to the date of original manufacture. If the pistol was made by a licensed manufacturer, the BATF&E could either check with the original manufacturer, if they were still in business, or a BATF&E would have the manufacturing records of a FFL holder that was no longer in business.

    To me the bigger problem is pre-81 machineguns were ruled as not existing. In the case of the pre 1981 unregistered DIASs, the courts have ruled that there is no such thing as a pre ruling machinegun that is not a machinegun. If a DIAS is a machinegun then the ones built before the ruling are machineguns.

    So the BATF&E has ruled that open bolt semiautomatic pistols are machineguns. The courts have ruled that there is no "grandfathering" machineguns. So that would seem to me that all those open bolt semiautomatic pistols should not have been registered as Title I firearms. They should be Title II firearms. So the big question is if the BATF&E made a mistake by allowing semiautomatic open bolt Title I firearms, will they give the owners the opportunity to register the open bolt semiautomatics as machineguns, or are those guns all contraband?

    Scott

  9. #9
    UZI Talk Supporter
    attherange's Avatar
    Join Date
    Aug 2007
    Posts
    1,673
    BATFE has and continues to contradict its self by reversing rulings that have been already deemed legal/illegal. The question I have is, if the ATF proceeds with indecisive decisions referring to the legalities of particular mechanisms, will they at some point be forced to flatly deny and or refuse the future possibilities of classification of questionable products? Just my thoughts.

  10. #10
    UZI Talk Life Member
    strobro32's Avatar
    Join Date
    Sep 2007
    Posts
    7,007
    Quote Originally Posted by hkg3k View Post
    "no-stamp with potential."

  11. #11
    UZI Talk Supporter
    Villafuego's Avatar
    Join Date
    Oct 2005
    Location
    Tampa, FL
    Posts
    624
    Quote Originally Posted by A&S Conversions View Post
    To be clear, if registering a Title I firearm to a Title II firearm that is a change in configuration. A change in configuration does not change the fact that the item remains a firearm built and logged in or registered by the original manufacturer. As far as the open bolt part, if the original pistol was home made there would need to be documentation as to the date of original manufacture. If the pistol was made by a licensed manufacturer, the BATF&E could either check with the original manufacturer, if they were still in business, or a BATF&E would have the manufacturing records of a FFL holder that was no longer in business.

    To me the bigger problem is pre-81 machineguns were ruled as not existing. In the case of the pre 1981 unregistered DIASs, the courts have ruled that there is no such thing as a pre ruling machinegun that is not a machinegun. If a DIAS is a machinegun then the ones built before the ruling are machineguns.

    So the BATF&E has ruled that open bolt semiautomatic pistols are machineguns. The courts have ruled that there is no "grandfathering" machineguns. So that would seem to me that all those open bolt semiautomatic pistols should not have been registered as Title I firearms. They should be Title II firearms. So the big question is if the BATF&E made a mistake by allowing semiautomatic open bolt Title I firearms, will they give the owners the opportunity to register the open bolt semiautomatics as machineguns, or are those guns all contraband?

    Scott
    Due to 922(o), any reclassification of pre-ruling open bolt semis would now result in them being contraband.

    The comparison to DIAS's is kind of apples to oranges.....as basically all DIAS's, "pre-81" or not, were determined to be MG's around 1998.

    The wording of the 1981 ruling regarding open bolt MACs doesn't "grandfather" anything.....it doesn't say that they are all MG's, or that any one manufactured prior to a set date is "grandfathered"....it states that only those manufactured after that same set date will be considered an MG...… wording is everything when it comes to the law...

    That being said.....they could still be reclassified at any time.....but since they are now selling for North of 1K, and not showing up converted to FA at a Miami coke-deal shootout every evening on the news, the probability of that happening is low
    Last edited by Villafuego; 04-28-2020 at 03:52 PM.

  12. #12
    Registered User KickStand's Avatar
    Join Date
    Jan 2018
    Location
    USA
    Posts
    582
    Iíve registered one or two of mine (canít remember).
    Before I registered them, I contacted BATF and they said I could register them as an SBR as long as itís not full auto. Iíve got the communication somewhere.

    U can always remove the firearm from the NFA registry and it would be just a regular (NON NFA) firearm.

    The stock block is welded in place on the bottom of the receiver. There should be three holes, the two smaller ones get welded in. However, I heard about people using the roll pin as a temporary fix but that might be dangerous and Iíve never tried it. Thereís automotive epoxy out there that Iím sure would work if you donít want to weld the stock block in. You can get a stock adapter that bolt to the bottom holes and use a different stock.

    Lastly, adding the original wire sock to the gun looks great but when collapsing the stock it will NOT slide in all the way due to the semi auto carriage in the lower receiver. I recall the stock will fold over the rear sight Though. You could cut the stock down about an inch and it would go in all the way.
    See pic below.

    Last edited by KickStand; 04-28-2020 at 05:20 PM.

  13. #13
    UZI Talk Supporter
    Gaujo's Avatar
    Join Date
    Sep 2013
    Location
    Raleigh, NC
    Posts
    2,586
    Advice: don't do it. Everybody round here that has one, takes it off and puts a fixed stock on it. It's a lot of trouble to get a stock that is generally considered flawed. Not to say nobody has the OEM stock, but I am saying people that compete almost always have something else.

    So, if you really want a stock, go for it, but I wouldn't do it for the OEM stock. I second what others said that a pistol brace increases the value of your firearm, whereas I would be willing to bet making this an SBR decreases this specific firearm's value. That's based on my assumption that the kind of people that like open bolt grandfathered Semi MACs tend not to be the kind that would want to inform the ATF that they have one.

    You've got a $1,000 gun there. Sell it, and you're $3,000 away from buying a transferable spitfire.

    my
    Last edited by Gaujo; 04-28-2020 at 05:27 PM.

  14. #14
    UZI Talk Supporter
    Offmarksman's Avatar
    Join Date
    Sep 2010
    Posts
    474
    I personally wouldn’t do it. I would leave it in its original configuration. These guns are $1,000 because they are collectible. If I wanted to put a stock on a semi, I’d put it on a closed bolt one. Just my opinion, it’s your gun, so do what you want.

  15. #15
    Registered User
    Join Date
    Oct 2018
    Posts
    22
    Quote Originally Posted by Gaujo View Post
    Advice: don't do it. Everybody round here that has one, takes it off and puts a fixed stock on it. It's a lot of trouble to get a stock that is generally considered flawed. Not to say nobody has the OEM stock, but I am saying people that compete almost always have something else.

    So, if you really want a stock, go for it, but I wouldn't do it for the OEM stock. I second what others said that a pistol brace increases the value of your firearm, whereas I would be willing to bet making this an SBR decreases this specific firearm's value. That's based on my assumption that the kind of people that like open bolt grandfathered Semi MACs tend not to be the kind that would want to inform the ATF that they have one.

    You've got a $1,000 gun there. Sell it, and you're $3,000 away from buying a transferable spitfire.

    my
    well I already have the OEM Stock, and if you have a transferable for 4k please let me know via PM I would like to set up a buy.

  16. #16
    Registered User
    Join Date
    Oct 2018
    Posts
    22
    Quote Originally Posted by KickStand View Post
    I’ve registered one or two of mine (can’t remember).
    Before I registered them, I contacted BATF and they said I could register them as an SBR as long as it’s not full auto. I’ve got the communication somewhere.

    U can always remove the firearm from the NFA registry and it would be just a regular (NON NFA) firearm.

    The stock block is welded in place on the bottom of the receiver. There should be three holes, the two smaller ones get welded in. However, I heard about people using the roll pin as a temporary fix but that might be dangerous and I’ve never tried it. There’s automotive epoxy out there that I’m sure would work if you don’t want to weld the stock block in. You can get a stock adapter that bolt to the bottom holes and use a different stock.

    Lastly, adding the original wire sock to the gun looks great but when collapsing the stock it will NOT slide in all the way due to the semi auto carriage in the lower receiver. I recall the stock will fold over the rear sight Though. You could cut the stock down about an inch and it would go in all the way.
    See pic below.

    Hey man nice! So ATF was ok with SBRing your open bolt semi MAC?

  17. #17
    Registered User
    Join Date
    Oct 2018
    Posts
    22
    To everyone, I actually tried calling the ATF today to ask about the legality of this issue, didn't get much of anywhere there. Value isn't something I am too worried about, I don't plan on selling it anytime soon.

  18. #18
    Registered User
    Join Date
    Oct 2018
    Posts
    22
    Quote Originally Posted by zipakna View Post
    i wonder if it would actually go through. since you are submitting a form 1, making you a manufacturer, and are applying to 'Make And Register a Firearm', though your intent is to make an SBR, the outcome firearm would be a open bolt firearm made after 1982.
    that is an interesting point you made but it looks like another member here has already gotten the green light from the ATF. The more I look into this the less I am motivated to carry out the SBR, I mean based solely on the fact that the stock won't even fit due to the semi auto plate in the lower. Then how it complicates things drastically if I ever try and sell the thing, not planning on it but you never know.

  19. #19
    UZI Talk Life Member
    zipakna's Avatar
    Join Date
    Jun 2011
    Location
    Virginia Beach Virginia
    Posts
    1,661
    Quote Originally Posted by CobrayStinger View Post
    that is an interesting point you made but it looks like another member here has already gotten the green light from the ATF. The more I look into this the less I am motivated to carry out the SBR, I mean based solely on the fact that the stock won't even fit due to the semi auto plate in the lower. Then how it complicates things drastically if I ever try and sell the thing, not planning on it but you never know.
    IMHO its a waste of time and money. soo many nicer things out there to SBR.

  20. #20
    Registered User
    Join Date
    Oct 2018
    Posts
    22
    Quote Originally Posted by zipakna View Post
    IMHO its a waste of time and money. soo many nicer things out there to SBR.
    yeah if it would be simple and just opening up those inserts on the back plate it would be one thing, but the semi auto sear plate really through a damper on the whole thing

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts


Please consider becoming an UZI Talk Supporter.