WOW, how did I miss this???
“The 1911 pistol remains the service pistol of choice in the eyes of those who understand the problem. Back when we audited the FBI academy in 1947, I was told that I ought not to use my pistol in their training program because it was not fair. Maybe the first thing one should demand of his sidearm is that it be unfair.”
— Guns & Ammo, January 2002
Let's do a history lesson.
The Colt Series 70
guns were introduced in 1971. Colt introduced the first major design change to the Government Model in nearly 50 years and in an attempt to improve the accuracy of production guns the barrel bushing was redesigned, along with the barrel. In this system the bushing utilized four spring-steel "fingers" that gripped the enlarged diameter of the muzzle end of the barrel as the gun returned to battery. By tightening the fit of barrel and bushing in this manner Colt was able to improve the accuracy of the average production gun, without going through the expense of hand fitting the older solid barrel bushing to the barrel and slide. Models using the new barrel/bushing setup were the Government Model and Gold Cup, which were designated the "Mark IV Series 70" or simply Series 70 pistols. It should be noted that the shorter 4 1/4" barreled Commander pistols retained the use of the older solid bushing design and thus were never designated Series 70 pistols, although one hears the term erroneously applied to Commanders from time to time.
The new "collet" bushing (as it came to be known) worked quite well, however it was prone to breakage if the inside diameter of the slide was too small as it caused the fingers to buckle, then later break from the stress of being wedged between the barrel and slide.
On pistols with oversized slides the bushing didn't grip well enough, and accuracy suffered. Because of this the collet bushing was eventually phased out sometime around 1988, with the older solid barrel bushing design being reinstated for use in production guns.
The Colt Series 80
introduced in 1983 known as the Colt "MK IV Series 80" pistols. The biggest change to the 1911 design came about in these guns when a new firing pin block safety system was incorporated.
A series of internal levers and a plunger positively blocked the firing pin from moving until the trigger was pressed, thus eliminating the possibility of the gun discharging if dropped onto a hard surface or struck hard.
of Colt's 1911-pattern pistols incorporated the new design change so even the Commander and Officer's ACP pistols became known as Series 80 guns. With the previous paragraph in mind, it is important to know that from 1983 until 1988 the early Government Model and Gold Cup Series 80 pistols used the Series 70-type barrel and bushing as well, although they were known only as Series 80 guns.
Another design change made to the Series 80 guns was a re-designed of the half-cock notch. On all models the notch was changed to a flat shelf instead of a hook, and it is located where half-cock is engaged just as the hammer begins to be pulled back. This way the half-cock notch will still perform its job of arresting the hammer fall should your thumb slip while manually cocking the pistol, yet there is no longer a hook to possibly break and allow the hammer to fall anyway. With the notch now located near the at-rest position, you can pull the trigger on a Series 80 while at half-cock and the hammer WILL
fall. However, since it was already near the at-rest position the hammer movement isn't sufficient to impact the firing pin with any amount of force.
1991 vs. 1911
The difference between these pistols is......... there is none. In 1991 Colt decided to market an economy version of their basic Series 80 Government Model. The polished blue was changed to an all-matte parkerized (later matte blue) finish, checkered rubber grip panels were used, and the serial number sequence was a resumption of the ones originally given to US military M1911A1 pistols. The resulting pistol was cleverly named "M1991A1", after the year of introduction. Mechanically however they are the same as any other Colt Series 80, 1911-type pistol. Around 2001 or so Colt upgraded these pistols with polished slide and frame flats, nicer-looking slide rollmarks, stainless barrels, and wood grips (blued models only). The newer ones are commonly called "New Rollmark (NRM)" pistols by Colt enthusiasts, to differentiate them from the "Old Rollmark (ORM)" 1991 pistols. The earlier guns are easily identified by having "COLT M1991A1" in large block letters across the left face of the slide. The NRM Colts will have three smaller lines of text saying "COLT'S-GOVERNMENT MODEL-.45 AUTOMATIC CALIBER", along with Colt's rampant pony logo.
The Colt Series 90
guns produced today are equipped with a 3" barrel and a captive dual recoil spring pack.
These are known as Compact or Ultra 45 ACP and include the Colt Defender:
And Colt New Agent:
On March 29th, 1911, the Browning-designed, Colt-produced .45 Automatic pistol, was selected as the official sidearm of the Armed Forces of U.S.A., and named Model 1911.
The Colt Model 1911 was slightly improved in early 1920's when the flat mainspring housing was replaced with an arched one, a shorter hammer spur was used, a short trigger was made standard as well as a longer grip safety. The new model was named Colt M-1911 A1 Government Model.
The same gun was produced after the war, with almost no changes in the original Browning's design.
Soon after the war, Colt introduced a new gun, based on the M-1911 A1 "Government" design, which was a shortened version of the M-1911 A1 pistol. This new gun featured a 4.25" barrel, (compared to the 5" of its prodecessor) and had an aluminum frame (for the first time this material was used in a handgun frame). The gun was called "Commander" (and not "Lightweight Commander" which was adopted later by Colt for this pistol) and was very well received by the public. In the years to come, Colt also produced the same pistol but with a steel frame, named "Combat Commander", and the term "Commander" has been used ever since to denote guns with 4.25" barrels.
Still later on, Colt introduced a pistol with an even shorter barrel (3.50"), targeting the concealed carry users, called "Officer's", which also had a shorter frame, thus using 6 round magazines. Again, this model name, is used today to denote the smallest model versions, with shorter barrel and frames.
[In the early 1970s, the Army decided to do something for its General Officers in terms of personal protection. The M1908 Colt Pocket Hammerless pistols issued to General Officers since World War II had finally outlived their service life. To correct this situation, Rock Island Arsenal, Rock Island, Illinois began modifying the standard M1911-A1. The pistol’s slide and barrel were shortened just over .75"(1.905cm) and the barrel had one locking lug removed. A full-length recoil spring guide was installed, as was an enlarged set of fixed sights. Checkered, walnut grip panels inlaid with a plate bearing the officer's name replaced the standard pistol's brown plastic grips. Adopted in 1972 as the United States Pistol, General Officers’, Caliber .45, M15, it is similar in both size and weight to the civilian Colt Combat Commander. The M15’s increased muzzle blast and recoil are a small price to pay for what is hoped to be a personal weapon of last resort.]
[During the nineties Colt announced their "Enhanced Series" of M-1911s, which were basically the Series 80 guns, with several modifications that most shooters would do on their pistols. Such modifications were a beavertail grip safety, beveled magazine well, flared ejection port, and a cut underneath the rear of the trigger guard, which allowed the pistol to sit lower in one's hand.]