sentences:  .38 Super pistols, on the other hand, can often work well with .38 ACP (or .38 ACP pressure-level) ammunition.They may require a slightly less-powerful recoil spring to function normally.Initially popular, the sales of the .38 ACP models dropped off with the introduction of the M-1905 in .45, and then the M-1911 caused sales of the .38 to essentially cease.