I was tired of my thumbs getting sore from loading my BDM mags, so I tried to come up with a easier way. I tried using some wire to push down the top of the spring and that did not work. Then I remembered the string mod to pull down the spring. I didn't want string hanging from my mags so I found some stiff wire and bent a hook on one end and a loop on the other end. I drilled a hole in the bottom cap. I put the wire in the hole and hook the spring at the top, then pull down and drop in the rounds. I hold the wire loop between my knees and the mag in one hand and drop the rounds in with the other hand. When the mag is full just twist the wire to unhook it. I only have skinny mags, so I don't know if it will work on full size mags. I used it at the range last week with no problems and no sore thumbs.