Hi Chris,
Yes, MGC .45 Thompson cartridges will work great in Hudson's M1A1
They're the only ones that I've ever used in my own M1A1.
Be sure to only use the MGC Thompson cartridges though, the .45ACP carts intended for MGC 1911 pistols are larger so will not fit.
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Cerwyn
Hobby collector of Replica model guns and Militaria.
also member of Living History Reenactment Groups.