The .45 Winchester Magnum is a longer cased version of the .45ACP, by some 200 thousands inch (.200) and has the same diameter bullet. The Mag is loaded massively heavier than the ACP, pushing the same weight bullets at almost twice the velocity. Needless to say my 1911 blowback action would not fair well with these kinds of pressures.
The .45 Colt or as you have it listed 45 Long Colt, is an original classic black powder round. The bore diameter has changed over the years and is now set at .454 inches, older ones are larger. Add to this that the original 'COPPER' cases were what is called 'Balloon' heads. The casing was mashed in upon itself to create the rim (think of .22 RF cases). This gave a little more space in the cartridge and made it much weaker than the current solid head design. The balloon head continued after cases started being made in brass. (If you find any balloon head brass, collectors will want it) All commercial loadings have to be concerned with the possibility of their newly manufactured ammo being fired in an original or reproduction weapon that was made for these much lower pressured black powder loading or smokeless equivalents. Thus the full potential of the .45 Colt will never be reached with commercial loadings.
All weapons will have a weakness or two or three. The classic Colt SSA has several but with proper ammunition will shoot very well (if you don't like anything more than a gully down the top strap for a rear site). The .45 Colt is not a Magnum round. The .45 Winchester Mag is.
I hope my long winded babble helped a little.
Enjoy and be safe.
Last edited by oldpapps; 11-07-2011 at 07:59 PM.