Keep in mind my explanation isn't going to be extremely scientific (i just got off the 10-6 shift), but it should be basic enough. (Assuming I'm as coherent as I think I am.)
When you pull the trigger and the slide moves rearward (caused by the Newtowian action=reaction mentioned aboved), most of the energy from the blast should be moving the slide rearward. A firm wrist allows this to happen by holding the frame still relative to the backward movement of the slide.
However, when the wrist is not firm, some of the energy that is supposed to be used to cycle the slide is also used in moving the frame back. So the slide doesn't move as far rearward relative to the frame (that's the important part) as it should. In some cases, this failure to cycle fully can result in misfeeds because the slide did not move rearward enough to "grab" the next round and slide it home.
It's basically an incomplete slide cycle.
That help any?
Which is why I limp wrist mine for a mag or two at every range session to make sure it'll function correctly.For self defense purposes, you do not want a pistol that is fussy about maintaining a perfect grip to ensure functioning. If, for instance, you have already been wounded, you will be lucky to hold the gun up at all, let alone maintain a firmly locked wrist.
That's because the momentum has alread been imparted to the slide by the firing of the cartridge.My Colt with the stock spring (~16lb) was bad to hang up with a limp wrist, but never fails with an 18.5. That seems backwards to me, seems like the heavier spring would be more picky but it works.
For self defense purposes, you do not want a pistol that is fussy about maintaining a perfect grip to ensure functioning. If, for instance, you have already been wounded, you will be lucky to hold the gun up at all, let alone maintain a firmly locked wrist.