Uh ... "mercury filling"?!? You mean the soft lead center post in the Hydra-Shok?
Back in the revolver days when .44MAG was approved for duty and off-duty (as long as jacketed or lead hollowpoints were used), there wasn't an abundance of loads from which to choose.
I did occasionally carry some various 240gr MAG loads, such as the Hydra-Shok, El Dorado Starfire and the Remington SJHP. Come to mention it, I still have a couple hundred of the Hydra-Shoks, as well as some of the Starfire 240's, left over from those days.
However, to try and reduce the potential for excessive threat perforation ("over-penetration") in the more urban areas, I preferred to find and carry Rem 180gr SJHP, Fed 180gr JHP or the W-W 210gr STHP, which I hoped would offer less penetration, depending on the circumstances. Eventually, due to concerns about excessive penetration in some areas, I started carrying .44SPL STHP, which made me realize that carrying a S&W N-frame or big Ruger, loaded with .44SPL loads was a waste of all that weight on my hip.
I seldom carry one of my .44's nowadays, preferring less weight for belt guns.