Barring a lucky hit, you aren't going to drop a charging grizzly with one or two hits from a .44mag, you hopefully cause it to break off the charge. The weight, trigger pull and recoil of a .44mag class handgun is such that two aimed shots may be all you get during the charge.
My point was that the 5N7 has comparable power to a 9mm but about a third of the recoil meaning the gun will stay on target giving you the chance to place quite a few rounds on target. With each shot fired (loud) and each new hit, you increase the chance of the bruin breaking off the charge. Aftermarket reloads using solid copper bullets mean hits to the head and large bones have a better chance of penetrating. Hit's to soft tissue will tumble less and penetrate deeper.
For an example as to why I say one or two hits from a .44mag class handgun to soft tissue won't drop a charging grizzly, see the video I linked at post #64 and be warned, it's graphic.
That’s why I recommended the larger calibers .454 or above which you can be quite accurate with in spite of their power and all you need is one shot with them as their terminal ballistics are devastating. The 57 though easier to handle will never stop a bear or moose as they have lots of fat and muscle which will slow the lighter bullet down considerably as it enters the flesh thus decreasing the liklihood of further damage. The larger heavier bullets penetrate deep and kill fast as they are not encumbered by the limitations. It is a proven fact in hunting dangerous game and is the reality of simple physics. KE = mv. Why don’t you take a 57 and go hunting for a grizzly to test your theory?