I bought one of these:

NC Star speedloader

It worked great, loaded maybe 10 mags with it then it stopped working worth a damn. There is a little plastic tab that stops the stripper clip from being pushed into the magazine with the rounds. It broke. There are such terrific reviews I'm thinking that maybe I got a defective example. I'm considering buying another and I'm looking for some people to speak up if they've used them a lot with success OR had a similar failure. I'd pay 30-40 bucks easy for an sheet metal example. Seems like plastic is all that's available.

I have M-14 mag spoons and they work with the 10 rd stripper clips I have in abundance but not as well as the tool linked above.

You will soon learn that NC Star has a poor reputation here. I personally have nothing good to say about them; I bought a 3x-9x scope from them that doesn't work worth a damn. Others will agree, and still others will echo my sentiments. Their quality is sketchy at best.