The "1911" in the name is because the pistol was adopted by the United States Army in the year 1911. M1911A1 pistols have an 'A1' added because they were changed from the original design in the 1920s in military service. The pistol was made first by Colt Manufacturing but was produced by many other companies during World War II. Because the M1911 is so popular, several gun companies make their own version of this gun which are still sold today.