David Marshall Williams is sent to a prison farm where he works in the tool shop and eventually develops the precursor of the famous M-1 Carbine automatic rifle used in World War II.
| Actor | Role |
|---|---|
 James StewartMarsh Williams | Marsh Williams |
 Jean HagenMaggie Williams | Maggie Williams |
 Wendell CoreyCapt. H.T. Peoples | Capt. H.T. Peoples |
 Carl Benton ReidClaude Williams | Claude Williams |
 Paul Stewart'Dutch' Kruger | 'Dutch' Kruger |
 Otto HulettMobley | Mobley |
 Rhys WilliamsRedwick Karson | Redwick Karson |
 Herbert HeyesLionel Daniels | Lionel Daniels |
 James ArnessLeon Williams | Leon Williams |
 Porter HallSam Markley | Sam Markley |
 Fay RoopeDistrict Attorney | District Attorney |
 Ralph DumkeAndrew White | Andrew White |
 Leif EricksonFeder | Feder |
 Henry CordenBill Stockton | Bill Stockton |
 Howard PetrieSheriff | Sheriff |
 Stuart RandallTom Vennar | Tom Vennar |
 Dan RissJesse Rimmer | Jesse Rimmer |
 Robert HyattDavid Williams (as Bobby Hyatt) | David Williams (as Bobby Hyatt) |
 Marlene LydenMary Eloise Williams (uncredited) | Mary Eloise Williams (uncredited) |
| LLovyss BradleyNot listed | Not listed |
 Frank RichardsTruex | Truex |