The problem with moonclips and .38spls/.357mags is that the rounds are kinds of long and spindly and it's hard to get them all lined up with the charge holes at once. And, naturally, the more of them, the harder it is, kind of like trying to hold a spider by the body and push all of it's legs into the holes. I had a gunsmith chamfer the charge holes fairly aggresively in my L-Comp and that helped a lot with loading moonclipped rounds. Speedloaders hold the rounds more stable and, in general, it's easier to load .38/.357 revolvers with them