IMO, that's like putting a Chevy 454 engine in a go-cart.  The scope is great, but it's just WAY more scope than an M4 needs, given it's limited effective range.  Personally, I wouldn't put that scope on anything that didn't have at least 800m of effective range, which means a .308 or larger.  An M4's effective range really isn't longer than 300 yards.  The M4, and .223 carbines in general, are best used as close-up weapons, which is why nearly everyone uses non-magnified optics on them.  The exception would be to use a BAC-equipped ACOG, which is nearly as fast up close, but does offer some magnification.

I would also not recommend mounting it on a carry handle; you'd be much better off changing the upper out to a flattop.  Magnified scopes really need to be mounted as close as possible to the bore, and flattop mounts are far more secure.  Due to the focal length of a magnified optic, anything 3X or more will make the front sight nearly invisible.  At the lower magnifications, there will be a shadow that you can see through, and even that will disappear at higher magnifications.

-Troy