The 45 Remington-Thompson was an attempt at an improved ‘intermediate’ cartridge up to 650 yards at a rate of 400 rounds per minute and manufactured in the 1923 Military Model Thompson. The picture above shows the Model 1923, but does not confirm whether it was for the Remington-Thomson or the standard 45 ACP.

The following is an excerpt from an article that appeared in 1932-33 from the American Institute of Criminal Law (via machinegunboards.com):

“An interesting development of the year 1922 was the Remington-Thompson .45 cartridge. This had a case or shell about one-eighth inch longer than standard, that it might not accidently be fired in a .45 caliber pistol. Results would have been disastrous because of the excessive pressure. This Remington-Thompson load used a 250 grain bullet driven at a muzzle velocity of 1,450 f.s. It had a penetration of about fifteen boards at the muzzle, and better than eight at the 300 yard mark. However its production was abandoned when it was found that the accuracy was not as great as that of the 230 grain standard load, and its 1,050 foot pounds muzzle energy as against 430 foot pounds for the standard load did not appear to deliver the increased shocking power which was expected of it. Guns using this cartridge were never sold commercially, although very complete tests were run by the Auto-Ordnance Corporation.”