Aaron Spuler is a firearms enthusiast and recreational shooter. Follow more or his work at The Weapon Blog
Breach Bang Clear has the details, this was an interesting read.
Basically, it looks and feels like a full magazine. And indeed it does function like a normal magazine too–at least for a few rounds, until 35 grams of TNT blows up in your face.
Read the rest of the article: http://www.breachbangclear.com/boobytrapped-mag-in-bosnia/