Note, there is a difference between a .38 Special and a .38 S&W. .38 S&W is a really short underpowered cartridge compared to the Special. From the picture it looks like the old .38 Special 200 gr. round nose loading. They were still making that loading in the early 1960s but I haven't seen them lately. I am guessing it was discontinued when much better powders were manufactured in the 1970s and 80s that would give a lighter bullet much higher velocities. I believe the Colt LDA came about to be used in the Colt Lightening, one of the first double action revolvers. It replalced the old .41 colt rim fire because of smokeless powder that wouldn't foul up the double action in the Colt.(An educated guess?) Monty