| .45 Remington–Thompson | |
| Origin: | Experimental military round |
| Design Date: | 1923 |
| Parent: | .45 ACP |
| Bullet: | .447 |
| Bullet Ref: | [1] |
| Case Length: | 1inches (about NaNinches longer than the .45 ACP) |
| Case Length Ref: | [2] |
| Bw1: | 250 gr |
| Vel1: | 1450ft/s |
| En1: | 1165lbft |
| Test Barrel Length: | 14 in (356 mm) |
The .45 Remington–Thompson (11.4x25mm) was an experimental firearms cartridge designed by Remington Arms and Auto Ordnance for the Model 1923 Thompson submachine gun, a variant of the Model 1921 with a longer barrel, with the intent of increasing the power and range of the weapon.[3] [4] While some variants of the 1923 were produced, the rifle and round did not find commercial success.[4]