.45 ACP

Browning designed it in 1904 for a US Army that had decided, after the Philippines, that it wanted a large-calibre service pistol again. The specification was a .45 bullet; what he built around it was a straight rimless case running at low pressure — 130 MPa, less than a third of a rifle round — and moving a very heavy bullet slowly.

That combination is the whole character of the cartridge and of the pistol built for it. Low pressure means a simple tilting-barrel lock and a slide that does not need to be heavy. A 15 g bullet at 250 m/s means recoil that arrives as a push rather than a snap, which is why the round remains popular in competition a century after the army that commissioned it moved on.

The three loads below all come from Federal’s own product pages, which state a five-inch test barrel — the length of a service M1911’s. That matters more here than for most cartridges: a .45 ACP fired from the 127 mm barrel these figures were measured in and from the 203 mm barrel of an M3 submachine gun are not the same round, and this page can only describe the first.

Gaps on this page: no ballistic coefficient is published for any of these loads, so the trajectory solver has nothing to work with and only the muzzle figures are computed. The encyclopedia’s own ballistics table carries five more loadings, but states no test barrel for any of them, and a velocity without the barrel that produced it is not recorded here.