The M43 by way of Canada is finally here! .... The fit on the sheath couldn't be snugger. Reminds me of skintight jeans...takes effort to get 'em off! .....
If you find the tightness annoying try removing one or both of the small blades, the chakma and karda. That provides more "give" on the inner side of the sheath and often is all you need to get a more relaxed fit for the main blade.