i have an M2K that I am quite fond of. The blade shape/size/sharpness etc seems to be just about "perfect" for me. But, like others have noticed and discussed the retention from the sheath isnt that great. What i did was get a ranger band, and put it to where it is toucht the back of the hanger. Then what you do is stretch that band over the front of the sheath opening about 1/3 of the way. Hard to describe w/out pix but...when you look at the sheath hole, you should now see a piece of your ranger band covering a part of the opening. When the knife is inserted into the hole, the band will make the hole "this much" less open and will grip the knife. Ive done the "shake the knife in sheath as hard as you can while it is upside down" test and the retention is there. I will try to post pix asap to show you this ez mod. Most of you will get what im saying, but like they say, a "picture is worth a thousand words".
Hope this helps!
Hope this helps!