The H&K MP5 is an icon around the world. Even its silhouette is recognizeable to anyone who has seen a movie or video game with guns in them. Here, close your eyes and think of the MP5 shape. What does the magazine look like to you?
I bet it looks something like this.
The standard curved mag of the HK MP5 is a steel box that holds 30 rounds of 9mm in a double stack column. Empty the magazine weighs around 179 grams. The curvature is supposed to help feed 9mm rounds although at one time H&K did make a straight magazine.
You can see the straight magazine above. It is a rectangular box with indentations on the leading edge so that it is easier to grasp and you can orient the magazine in the dark.
The straight mag is a little lighter at 171 grams. If you look at the markings above it is stamped SD. That is believed to have been made for the MP5SD.
The SD stamped straight magazines have a plastic follower whereas the curved magazines and non SD stamped straight magazines have metal followers. It is reportedly to reduce followr noise for shooting suppressed.
Next up is a rather uncommon magazine for the MP5, it is the MKE polymer magazine. MKE is a military weapons and ammunition manufacturer in Turkey. They purchased the tooling for MP5s from Heckler & Koch. MKE made a polymer magazine for the MP5. It is half the weight of a metal magazine at only 85 grams. It is a dark smoke plastic that is somewhat translucent but you need to have bright light shining to see the bullets in the magazine. Some say they are not realible and the plastic feedlips can break with a lot of use.
The last magazine is an extended curved mag made in the USA. It holds 38 rounds although you could squeeze in 40 rounds but it is not reliable. It is the heaviest out of the bunch at 195 grams.
The standard 30 rd curved magazines can usually be purchased for around $30 - $75 depending on where the magazine is made. The cheaper ones are made in Korea and the H&K SP5K magazine is $75. I found an online store that was selling the MKE polymer magazine for $28 and I got the long extended 38 round mag from HKparts for $58. The straight metal SD magazine came direct from Germany thanks to a co-worker.