L- those look ok But they're quite bulky and might 'dump' if mis-handled. Stripper clips will retain bullets quite well, and can be adjusted if necessary. And are much cheaper. There are 'speed-loaders' sold to make loading the clips simpler, too. I prefer using removable mags, but I have Tapco . . . some brands are not as good, I hear. I also have a bunch of clips, that can be used to 'reload' the mags while they are in the rifle. Some removable mags - such as Tapco - need minor filing to allow them to work well with clips.
In other words, there are lots of options out there . . . I'd go slow on buying 'things' until you can 'see 'em in action'. That vid of the loader was pretty brief, but it might be a good tool. I'd want to see more vids, like how it needs to be handled - will it 'dump' if inverted - or laid down on it's side, etc. I'm just a cautious shopper. HA !