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50 rd drum magazine

Dbbaker1002Dbbaker1002 Member Posts: 2

I have a 1927A1 Thompson Arms with a 50 rd drum mag and a 20 rd stick mag. The "Chicago typewriter" is new and is the semi-auto version. The stick mag fires without malfunction or jamming. I am using the recommended 230 gr FMJ ammo. The drum mag jams after one or two fired rds. Is there a trick to using this type of magazine? Any help is appreciated.


  • MobuckMobuck Member Posts: 13,176 ✭✭✭✭

    Have you tried it with 5-10 rounds loaded? The sheer weight of the drum and 50 rounds of 45 ACP can be enough to throw the feed angles off.

  • AmbroseAmbrose Member Posts: 3,062 ✭✭✭

    I just read a book about the D-Day invasion and there were issues with the 30 round Thompson sticks. It appeared that even 30 rounds was too much weight for reliable function. I hope you get it going: a Thompson is even more impressive with a drum mag!

  • truthfultruthful Member Posts: 1,819 ✭✭✭✭

    50 rounds of 230gr .45ACP plus the drum is a fair amount of weight to hang off a magazine catch. You said that the drum mag jams. So you mean that the drum does not feed a round, or does a fed round jam the gun action?

  • mark christianmark christian Forums Admins, Member, Moderator Posts: 24,498 ******
    edited May 2022

    When the semi autos were first offered by Numrich Arms they found that getting the new style drum (original TSMG drums and unaltered box magazines will not fit the semis) to handle a full 50 rounds was difficult. For that reason the first run of drum magazines held 39 rounds.

    You can look on line for various tips and modifications which might enable the current 50 round drums to feed and function. A lot of it is hit and miss. Good luck.

  • jwb267jwb267 Member Posts: 19,671 ✭✭✭
    edited May 2022

    you might try a little graphite

    Excellent suggestion. I recall the BETA C-Mags came with a small tube of graphite lube. Mark C.

  • Dbbaker1002Dbbaker1002 Member Posts: 2

    Thanks to all that replied. Looks like I have my work cut out for me.

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