Probably the last really serious attempt by Colt to compete in the LEO revolver market were the later Troopers (Mk III) and Detective Specials produced in the late 1960s - early 1970s. They were very nice guns but the Smiths were cheaper and more durable, heavy on the cheaper. I worked with a couple of guys who had the later D.S. as personally owned duty guns and they were beautiful guns with very smooth actions, but even the guys who bought their own were buying Chiefs at the rate of at least 3-1 over the Colts. The Border Patrol bought a bunch of Troopers at one time but the Patrol after a brief flirtation with the Troopers went back to Model 19s and eventually on to their last issue revolver, Ruger .357s. The Rugers were great duty revolvers, robust, reliable and accurate, though their actions felt a bit funky to someone who cut their teeth on Smiths and Colts, but by the time the old INS adopted them for the Patrol and Special Agents the day of the revolver as a law enforcement tool was nearly over, they were obsolescent almost from the day they were introduced. But since the Border Patrol back then was said to have "50 years of tradition uninterrupted by progress" they kept wheel guns much longer than other agencies, hanging onto them as issue weapons well into the 90s.