There's not much spring resistance in those 25 rounds banana mags to make it difficult to load by hand. As you found out, the BabyUplulas don't work so I just load them without any tool. I don't think it'll be any faster with one but I could be wrong. I like the 25 round mags better with the 512 semi-auto action than on the 455. Sorry, I don't have any suggestions for a loading tool.