Ah yes.... The Old Fuff at least does know the difference.
Over the years certain dimensions in the 1911 design were tweaked to insure that components (including frames, slides, barrels, and all other parts) that were made by various contractors would interchange into guns made by others. The goal was total interchangeability. At the same time adjustments were made to what I call
calculated clearances to insure that the pistol would function regardless of the environmental circumstances. Contrary to what some believe, these clearances were not limited to making space for mud, sand and other kinds of fouling – but also to give the system a little leeway during the extraction/ejection and feeding cycle. These to a considerable degree account for the reason that the older guns are more reliable then the newest ones, where manufacturers – including Colt – have tightened the clearances to make the pistol (at least in theory if not practice) more accurate. This said, clearances are only part of a larger picture when it comes to the way these pistols are dimensioned today.
But since no manufactured dimension is absolute from part to part, tolerances are included (so much plus, so much minus) to insure the part will be made within a reasonable range on each dimension. Here I often find that currently manufactured parts often don’t meet the requirements shown in the government’s blueprints. In some cases this is deliberate, in others it shows sloppy workmanship and/or a lack of inspection.
During the late 1950’s and 1960’s Government engineers working first at the U.S. Army’s Springfield Armory and later Rock Island Arsenal, developed a system to mass produce match grade 1911A1 pistols for use in certain government sponsored bullseye target matches. While these pistols were substantially more accurate then an average service pistol, they were not intended to be services pistols. However the procedures, parts, dimensions, and tolerances used in the match weapons program are largely used today by makes of current 1911 style pistols. This practice works well with the big-boy toy concept, but not so well for those that want a true USGI weapon or the commercial equivalent once made by Colt.
Incidentally, for those who might be interested, match-grade pistols often require a breaking in period before they become reasonably reliable for a non-weapons purpose (punching paper or addressing steel targets), while 1911 service pistols (weapons) never did. It’s all in their respective clearances and tolerances.
