Allen
Changes from series 70 to 80
Sunday, July 15, 2018, 12:32

The single biggest change to the 1911 design came about in 1983, when Colt introduced the "MK IV Series 80" pistols. These guns incorporated a new firing pin block safety system, where 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. In this instance however, ALL 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.

There was one other design change made to the Series 80 guns as well, and that was a re-designed 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. don’t bet your life on it.