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Thread: MAC M10 issues

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    MAC M10 issues

    I finally got my Texas MAC M10 to my FFL on a Form 4. Went to test it today and had some issues. First was the 9mm upper. I put the upper on along with the magwell adapter. Inserted the mag, pulled the knob back, pulled the trigger and nothing happened. When I take the mag out and pull the trigger it goes home. Maybe bad mag, I only brought 1 with me. The mag is a single feed and I believe the bolt is also, not sure. The .45 upper was better as it fired. But, when I tried to do a mag dump, it fires a burst (5-7 rounds). Never fires the whole mag. Maybe need new sear? Thanks for the help.

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    Registered User LawBob's Avatar
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    You need to post Pics

    You said the mag is single feed. Well most m10/9 Texas macs are double feed. Is this an swd Texas mac or a true Texas Mac? Need pics.


    Perhaps they gave you a sf mag and you have a double feed bolt. Wont clear the inner feed lips.

    The lack of firing all the rounds in 45 is not likely a sear issue. Its probably a ramp issue imo on the feed ramp.

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    Registered User LawBob's Avatar
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    I assume you changed bolts also

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    Yes, I have 3 .45 uppers and 1 9mm upper. Only one of the .45 uppers have a bolt. The 9mm has a bolt also. It is in the safe of the LGS as it just came from a Form 4. Will be sometime before I go back because I need to pay stamps.

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    Also is a SWD completed model with the Cobray logo. Logo looks to be an original stamped logo.

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    The burst fire in 45 is likely the S/A trip spring. You can replace the spring or simply remove the semi auto trip. I did the latter as I have no desire to shoot the M10 in S/A. I've had this issue on a couple of macs.

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    If the cobray logo looks original it may be an early TX Mac. I think he produced some before they made him grind off the Cobray logo. SWD put the logo back in the spot it had been ground off of.

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    Registered User LawBob's Avatar
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    Quote Originally Posted by AK74U View Post
    Also is a SWD completed model with the Cobray logo. Logo looks to be an original stamped logo.
    Ok, so this still has a 45 magwell and you are using a 9mm insert

    Most likely that’s a df magwell adapter to use the Walter mags, not the swd zytel mags

    Is it possible you have a df bolt, but are using at zytel mags? That is, The bolt cannot slide through the opening of the back of the sf mag.

    Take bolt out and see if the back of the (empty) mag opening can slide through the part of the bolt that strips the bullet off.

    Also: if is used df mags, the mag catch isn’t interchangeable between the 9 and 45, you have to change it. Mag may be sitting too high.
    Last edited by LawBob; 06-26-2021 at 10:04 AM.

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    Yes but it has the side safety and not the Garand style safety in the trigger guard. I know the mags are plastic Cobray marked for the 9mm. I'll take pics of the 9mm bolt.

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    Registered User LawBob's Avatar
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    Yeah it’s a swd completed gun. I assume that swd guns would use zytel

    Perhaps it was a 45 gun and someone purchased the magwell adapter and a 9mm bolt after the fact- and bought a df bolt


    Or perhaps the 45 mag catch makes the zytel mag sit too high inside and the bolt is hitting it.

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    I can't upload the pics. Says that the file can't be resized and needs to be uploaded manually.

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    Registered User LawBob's Avatar
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    Need to use a hosting service like

    Imgur.com

    Then link here the pic there.

    Google and Amazon also do this but then again they are inherently evil

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    SWD was not the only manufacturer or Gunsmith to "upgrade" TX registered receivers. Sam told me he has done a bunch of Texas M10 upgrades. I am sure that he is not the only one.

    Scott

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    Registered User LawBob's Avatar
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    I know. He did Mine. But the author said his is a SWD completed Mac in the thread above.

    What’s more rare is it to be a 45, not a 9.

    I don’t profess to know whether swd used zytels or walther type 9mm mags when it was a 45 magwell being used with a magwell insert to convert it to 9mm. Maybe they never did that. They may have just sold it as a 45 only. Dunno.

    Mine uses walther, and a df bolt. The original Texas Mac 9 upper is df bolt and used DF mags (mine was 45 w the 9mm conversion kit from Leatherwood).

    He mentioned he has a zytel mag, sf.

    If this was a 45 gun completed by swd, who knows who paired up the 9mm upper, magwell insert, and bolt. Maybe they assumed any 9 bolt would work or any 9 mag would work. Or maybe the author bought zytels assuming that would work. Dunno.

    As one guess, he’s got a Df bolt and a sf zytel mag (a mismatch) and the bolt is slamming into the back of the mag.

    Another possibility is that the mag catch is 45 and is holding the zytel too high for the bolt to clear. That may be easily dismissed bc someone here may know whether a 45 mag catch would hold a 9mm magazine too high or too low. I haven’t farted w the 9mm upper since I sold my large steel 9mm upper 7 years ago. I have an unfired Lage mk2 9 upper but I haven’t shot it bc I have to fit it to the lower (my lower’s hood isn’t quite square inside).

    Those are my two guesses.
    Last edited by LawBob; 06-26-2021 at 06:54 PM.

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    Registered User LawBob's Avatar
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    Quote Originally Posted by AK74U View Post
    Also is a SWD completed model with the Cobray logo. Logo looks to be an original stamped logo.
    Nm

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    I'll try to use the first site to upload the pics.

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    Regarding the 9mm upper and mag adapter:

    -The bolt won't go forward because its hanging up on something and not picking up the cartridge and slamming it home into the chamber:
    with the gun empty and an unloaded mag, check to see if it hangs up. take some pictures of what its hanging up on by looking through the ejection port.
    1. It could be the mag and the bolt are hitting - as others have said a double wide bolt with a single feed mag - bolt is to fat to move across the mag feed lip gap. get the right mag for the bolt.
    2. Mag height could be too high and catch or mag needs adjustment

    Regarding the 45. If it feeds most of the time

    I would suggest:
    -Try a different, preferably new(ish) magazine or replace magazine springs. Grease gun mags are often WW2 vintage and vary in wear when you get them - but Keepshooting.com has new replacement springs some NOS mags still exist for sale.
    The magazine spring has to be strong enough to lift a cartridge in the position by the time the relatively fast bolt is moving back home to chamber - if the mag springs are aorn - this can cause feeding issues.

    -Try different factory ammunition, MACs should feed well with good factory ball ammo, but some ammo loads I've seen ESPECIALLY from recent new ammo give inconsistent results - high output (perhaps hurried) manufacture in especially in my 45 where the rate of fire slows and increases within the same box - meaning ammo is likely not loaded consistently precise. Some brands run less reliably than others as well. Lots of ammo is on the she shelf is good and It may be completely "safe" for use and run some guns, but not ideal for a machinegun reliability. Try some different brands.

    - Clean lube the gun completely and inspect parts, It probably wouldn't hurt to change out a recoil spring on the bolt. check sear engagement and feel for friction points. I wouldn't tear it apart unnecessarily and swap parts unless something was amiss with a certain part.

    -check extractor for wear - you can find replacement extractors for the old style bolts or find a newer bolt with the better extractor. (cases may not be clearing the gun and bolt closes on brass or jamming up the works)

    Pictures of the jams would help find root cause.

    Good luck.

  20. #20
    Registered User LawBob's Avatar
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    Quote Originally Posted by AK74U View Post
    Need pic of the bolt and mag Back (the u shape the part of the bolt slides though to pick up the cartridge) together in perspective.

    I can’t tell from that picture if it’s sf or Df bolt. Although it seems to be more of a v shape, likely sf. That’s a zytel sf mag for sure.

    If that’s a sf bolt then your issue is prob the mag catch is holding the mag too high. As said above, put emty mag in pull bolt back and fire. Take picture from ejection port.

    If it’s too high, you’ll need a 9mm mag catch. Usmachinegun.net but I couldn’t swear it’s the same as an rpb 9mm mag catch. Maybe swd used m11/9 Mag catches

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