I started in LE in 1970, we were issued Colt Python 4" and a 12 round cartridge slide. Part of our training curriculum was learning to "speedload" and I use the term loosely, with cartridges from the slide to the gun.

2 rounds at a time from the slide into the empty cylinder. Thank God for HKS when they introduced a reliable, easy to use speedloader in the early 70s. I still use the 2 rounds at a time today when not in a hurry to reload. First carried a Model 15 4" in the AF in 1965. Cartridge loops there also. Dump pouches were a pain in the butt, fumbled the reload with them a lot, but they cut down on the space the slide took up on the belt.