I was wondering how you take these guys apart. I am holding one right now but can’t seem to figure it out. Thanks!
Join the club buddy.
Ar15.com use to have a sticky on it but its gone now and I would like to figure this out also.
All i remember is something about pushing on the rubber knob on the bottem.
Rob
it’s much simpler to do than to describe below. don’t push on that rubber knob, though.
in the middle of the ‘outer’ floor plate is an elongated hole/slot. use a bullet, pen - anything that fits in there to push the ‘inner floorplate’ in (it only has to go in 1/8" or less) while pushing the outer floorplate towards the rubber ‘button’ (back of the magazine) and lifting up the floorplate. this will compress the rubber button and allow the tab on the floorplate to pop out of the slot at the front of the magazine and come off.
assembly is in reverse - place the outer floorplate on top of the inner floorplate and insert the rear tab (rubber button end) into the slot in the magazine body. use the bullet to push the inner floorplate down while pushing the outer floorplate back to compress the rubber button. it’ll pop back down and engage the front slot.
I have a copy of the H&K Factory “Operator Instructions for the High Reliability Magazine” on Adobe PDF format if anyone is interested. These H&K instructions cover the disassembly, assembly, and maintenance of this magazine. Also makes for interesting reading!
If anyone is interested in a copy, shoot me a e-mail and I will respond with an Adobe PDF formatted copy. 
Thanks for the instructions brother!
They are pretty simple once you do it.