Your 629-4 is one of the better .44 Mags built by S&W.
It should handle factory 240-gr Magnum loads without any issues.
I have settled on a couple of factory loads for my .44 Mag S&W's.
Winchester Silvertip 210-gr, if I happen to be carrying one of my .44 Mags as a defensive weapon.
The other is Winchester White Box 240-gr JSP. I have stocked up on several boxes of this, as it's reasonably priced, accurate, reliable, and an excellent general-purpose round.
-Jim